The scene is set for the storm of the century as Hurricane Iris, a particularly violent squall, threatens south Florida. Patrons at a local convenience store stock up on supplies, readying themselves for the storm, where a young boy is caught shoplifting by a cashier. Bolting from the store to avoid capture, he stumbles into a wooded area and discovers a woman lying dead in the bushes, a gunshot wound to her chest.
Outside the store, Longworth and Sanchez show up to canvass the crime scene, Longworth taking inventory of the woman's wallet and Sanchez inspecting the body. From the contents of the wallet (which is absent of cash), Longworth discovers the woman's name is Valerie Raines. Sanchez suggests that based on the scene, the motive of the murder was robbery, but Longworth disagrees, noting that the woman's driver's license and another card appear to be missing while all the credit cards have been left untouched.
Sanchez tells Longworth they have to put the investigation on ice until after the hurricane because they shouldn't be outdoors and he is needed at the hospital, but Jim is too busy staring into the distance at the approaching storm. He tells Sanchez this will be his first hurricane and Sanchez tries to convey just how serious what they're about to experience is as the ominous wind swirls around them.
Callie and Longworth meet up at the hospital, where Longworth has come to look at the body of Valerie Raines. Longworth gives Callie an update on the case, telling her he doubts robbery was truly a motive in the crime, but Callie is distracted by a phone call informing her that Hurricane Iris has just been upgraded from a Category 2 to a Category 4. She worries aloud that Jeff is home alone and Longworth offers to pick him up and drop him off at the hospital which Callie gratefully agrees to, giving Longworth an appreciative squeeze on the arm which they both seem to register.
Meanwhile, the police station has been turned into an emergency operations center during the hurricane, with Colleen Manus at the helm. Daniel Green arrives to help as Manus runs around, trying to direct perps into empty rooms since the holding cells are all full and requesting that the mayor issue a mandatory evacuation. It's clear it will be a long 48 hours.
Longworth and Jeff make it back to the crowded hospital with Jeff's pet lizard, Iggy, in tow. Longworth poo poos the severity of the hurricane, but it's obvious it's making him nervous. Callie brings news that a homeless woman came in earlier trying to use the insurance card of Valerie Raines and Longworth goes to speak with her.
Longworth finds the homeless woman sitting next to Carol Watkins, the hospital administrator, who is holding her for Longworth to question. Watkins hands Longworth Valerie Raines' driver's license and insurance card. The homeless woman tells Longworth she stole the cards from the dead woman but only because she was sick, and assures him she saw nothing. Watkins wants Longworth to charge the homeless woman with a crime, but Longworth instead tells her to treat her and send him the bill.
At the station, Manus handles the overflow of hurricane-related crises when Daniel arrives to let her know another person has been shot.
The rain and wind are beginning to pick up as Sanchez and Longworth huddle around a limousine, investigating the latest dead body. The deceased turns out to be Dennis Peterson, a motivational speaker and self-help writer shot with a 9-millimeter hollow-point bullet, the same kind that killed Valerie Raines. Longworth and Sanchez suddenly realize they are dealing with a spree killing.
The team combs through the limo, searching for evidence to connect the two victims. Longworth checks Peterson's license, canceling out one connection as he determines that while Dennis Peterson was a New York resident, Valerie Raines was a local. From Peterson's cell phone calendar, Longworth determines that the author was to be at a speaking engagement in just a few hours. Despite Sanchez's protests about the hurricane and the fact that his lab is being used in the evacuation route, Longworth demands that he complete the ballistics report on the bullets by the end of the day.
Longworth interviews the young limo driver who tells him he was taking Peterson to his speaking engagement, but the impending hurricane seemed to change the author's mind about attending. They stopped for a cappuccino for Peterson, which the limo driver says he ran inside to get, and when he came back he found Peterson dead, the sight upsetting him so much that he spilled the cappuccino all over himself. He adds that Peterson was his favorite customer, a big tipper and was always trying to make him less of a slacker. Longworth asks if Peterson had visited the city often and the limo driver tells him three times in the last month.
Inside the coffee shop, Longworth speaks to an apathetic female barista who confirms the limo driver did come in to order a cappuccino. As he turns to watch the hallowing winds outside, Longworth nervously spills coffee on his hand. A patron in the store senses Longworth's uncertainty and confirms his worst fears - that things are about to get even worse.
Back at the hospital, the mood is one of controlled chaos, as Callie and Sanchez spot and recognize each other in the disorder and Sanchez asks for her help in finding a spectrometer to do his bullet analysis. Callie obliges, asking him to repay the favor by taking a patient with him as he goes. That patient is 84 year-old Evelyn Fisher who freaks out when Sanchez tells her he's a coroner, thinking she must be dying.
Longworth makes a stop at The Grand Hotel, where Dennis Peterson was staying while in Florida, and questions the concierge, who tells him Peterson checked out a few hours before, as positive and friendly as usual. When asked about Peterson's stay at the hotel, the concierge tells Longworth the author was in town for speaking engagements, but Longworth quickly pokes a hole in his story, telling him he has Peterson's calendar which did not show any speaking engagements listed. The concierge pulls the guest privacy card, but Longworth persists until he finally reveals that each time Peterson was in town a doctor came to visit him and Peterson would follow up each of these visits with a spa visit at the hotel.
Later, as the rain pours down, Longworth tries Callie to no avail. He answers the phone when it rings again, but it's Manus on the other line offering information on the case from the extremely busy and chaotic station. Manus tells Longworth that Valerie Raines worked as a Human Resources Director for a local medical instruments manufacturing company, but that they're having trouble getting an employee list because of the storm. She also tells him that Sanchez has confirmed the same gun killed both Valerie Raines and Dennis Peterson. Hearing the storm behind him, Manus urges Longworth to get indoors and he tells her he plans to - at the location where Peterson was supposed to have his speaking engagement.
Inside the Palm Glade Hotel, Longworth spots a large image of Dennis Peterson as featured speaker, but before he can take it in, a woman mistakenly engages Longworth in conversation, thinking he is someone named Bill Taylor. The woman, former high school prom queen Tanya Owens, makes small talk about the Palm Glade Class of 1990 reunion being held in the hotel that afternoon, giving Longworth a bright idea. At the welcome table, Longworth tests out his new identity as Bill Taylor, warmly hugging a woman named Becky Manning as over his shoulder he spots unclaimed nametags for both Dennis Peterson and Valerie Raines, the two victims.
Longworth chitchats with Becky, making sure to ask if she thinks Dennis Peterson will show, when ex-jock Eddie Strickland approaches them. Longworth notes the subtle tension between Becky and Eddie, the latter of whom has a coarse, suspicious attitude, especially about Peterson. The group walks into the ballroom where Eddie heads straight for the bar.
Longworth's cell phone rings; it's Callie. Longworth asks Callie if she can find out if the doctor who visiting Peterson at the hotel came from her hospital. Callie reminds him that the information is confidential and Longworth reveals he is dealing with a spree killing and asks her to please tell him if she thinks of anything he should know. Just then Callie's other line rings, a call from her husband in jail, and hangs up with Longworth to take it, assuring him she see what she can do.
In jail, Ray Cargill, Callie's husband, questions Callie about her and Jeff's whereabouts in light of the hurricane. Ray tries to sweet talk Callie, but she isn't having it so he asks to speak to his son. Callie watches Jeff talk to his father for a minute, then hurries away to go deal with the growing chaos in the hospital ward.
Back at the Palm Glade hotel, Longworth flips through the 1990 class yearbook, stopping on a photo Dennis Peterson and another boy Jason Hilgard, who made up the school's Chess Club. Longworth spots the adult Jason Hilgard across the room, but is intercepted by a pretty, surgically-enhanced woman named Nicole Gelber. Mistaking Longworth for Bill Taylor, Nicole reveals she's always had a crush on him and begs him to dance. Longworth declines for the moment and moves to Jason Hilgard, who has penciled in on his nametag that he is now Dr. Jason Hilgard.
Hilgard tries to remember Longworth's alias, Bill Taylor. He grasps for something and then reminds him they had geography together. Longworth flatters Hilgard about being the smartest one in the class and uses his knowledge of the Hilgard's connection to Peterson to get information out of him. Hilgard tells Longworth he and Peterson drifted apart after high school and mentions he's sure Peterson would've liked to be there, given he slept with every girl at the school.
Just then Longworth's phone rings again. It's Manus, reporting that a third body has been discovered in St. Pete, a bank officer by the name of Charles Kendrick, killed with the same gun as the other two. Hearing Madonna playing in the background, she asks Longworth where he is and he tells her about the reunion and the victim connection to it. Manus tells Longworth the new victim is likely not connected as he is older and from Georgia, but Longworth explains that he could've been on his way over to the reunion. He tells Manus the killer isn't stopping because of the hurricane and neither will he.
In the men's room of the Palm Glade Hotel, Longworth runs into Eddie Strickland who has come into the bathroom to brood and smoke. Blocking the exit, Longworth questions Eddie about his high school football career, deciding that only a former athlete with no sports career and nothing to live for would take up smoking. Eddie explains that he delivers water to rich people too good to drink from the tap and hates that all people do at reunions is show off. Longworth asks him if he feels that way, why did he come and Eddie offers that maybe he just wanted to see what giant asswipes everyone had become.
Sanchez runs into elderly patient Evelyn Fisher again at the hospital and asks her how she's feeling. They chat, enjoying each other's company, and Sanchez tells her he will make a special effort to watch out for her. Evelyn says Sanchez he would've made a great doctor, given his wonderful bedside manner and compares him to her husband, who she says made her a lucky woman. Sanchez tells Evelyn her husband seems to have also been a lucky man and the two smile kindly at each other, but their sweet moment is cut short when Evelyn clutches her chest and falls to the ground.
Sanchez quickly calls for help and begins CPR. Callie comes to Sanchez's aid and inserts a ventilator to help Evelyn breathe, but just as she does, the power goes out. Sanchez switches the electric ventilator with a manual one and begins to pump air into Evelyn's lungs himself. Then, getting an idea, he asks Callie to take over and runs into the darkness. As she wonders where he's gone...
Sanchez ducks into a makeshift FEMA warehouse outside the hospital, searching for supplies. He tells an overworked FEMA manager that the generator in the hospital has just blown and that he needed to use one of the four the agency has. The FEMA manager tells him that the four generators are all already in route to other locations and she simply doesn't have one to spare. Quickly devising a new plan, Sanchez calls intern Daniel Green and puts him to the task of finding a new generator.
Manus phones Longworth from the police station, where a tree has crashed into one of the windows and officers are feverishly trying to board it up. She once again hears the music playing in the background and tells Longworth he needs to get this state of emergency with the spree killer under control and stop goofing off.
Ending his call with Manus, Longworth swoops in to speak to Becky, telling her he and Dennis Peterson are friends on Facebook, a fact which seems to excite her. Longworth plays into this excitement, telling her Peterson talks about her all the time and wants to dedicate his next book to her, insinuating he knows about their sexual history. Weirdly, Becky calls her husband over to tell him the exciting news, making it clear he too knows about her liaison with Peterson. As Longworth considers this...
Sanchez and Green put their plan to get a generator into action, Sanchez apologizing to the FEMA manager for the stress he's causing him and distracting him while Green sneaks into the man's office and steals keys for the truck. Having secured the keys, Green and Sanchez gun the truck's engine and begin to back it out of the warehouse.
Still making his rounds at the reunion, Longworth is "recognized" by another pretty female who smacks him hard on the cheek, payback, no doubt, from a slight by Bill Taylor. Suddenly, a drunken man spots Longworth and blows his cover in front of Eddie Strickland, telling Longworth he's not Bill Taylor, that in fact the real Bill Taylor e-mailed him that he couldn't make it. Realizing the gig is up, Longworth flashes his badge and tells Eddie Strickland they need to talk.
Pulling out the yearbook, Longworth shows Eddie a picture of his younger self, his arm around Becky, ever the confident football player and cheerleader couple. That is, he says, until Peterson moved in and stole Eddie's girl. Longworth questions Eddie about his anger at Peterson for stealing his girlfriend and then going on to accomplish big things, making him one of the "asswipes" Longworth described earlier. Eddie knows where Longworth is going with his line of questioning and asserts that he was stuck in traffic on the road and didn't kill anyone. Still, Longworth leaves him with two security guards, explaining he cant go home just yet.
Sanchez and Green return to the hospital and are met immediately by Carole Watkins, the hospital administrator, who is furious with them for stealing the generator. Se tells them plugging in the generator puts the hospital at criminal risk and she won't let that happen. Sanchez pleads that people will die unless they have use generator. Then, making an executive decision, he pushes past Watkins, determined to go save lives come hell or high water.
Back at the Palm Glade Hotel safe from the gales of Hurricane Iris, Longworth is approached by Nicole Gelber who hits him up for the dance he promised her. As they dance, Nicole admits she knew Longworth wasn't Bill Taylor but that she kept his secret because he was cute and the reunion was boring. Longworth asks her if Peterson had any connection to Valerie Raines and Nicole tells him no, though Peterson could have any girl he wanted in high school. Any girl, that is, except homecoming queen Tanya Owens, who was already taken. Longworth thinks about this as they continue to dance.
Longworth stares at the photo of Tanya Owens, the homecoming queen he met briefly on his way into the reunion. In the photo, an 18 year-old Tanya stands with a boy above a caption that reads "Tommy and Tanya, Homecoming King and Queen." Nicole tells Longworth that Tommy Owens and Tanya had been going out since senior year, but Longworth counters relationships didn't seem to stop Dennis Peterson from moving in on women, as evidenced by Becky Manning's situation. Nicole continues that Tanya and Tommy got married right out of high school, had a baby, then fell on hard times because of some medical issues and may possibly be getting a divorce.
Longworth's cell phone rings. It's Callie, with confidential information on Dennis Peterson. As it turns out, Peterson was donating bone marrow to a 20-year-old boy who, it turns out, is his illegitimate son. Longworth doesn't need Callie to tell him the boy's last name is "Owens," as it becomes very clear that the child is the "son" of Tommy Owens. Longworth looks down at the photo of Tommy in the yearbook and suddenly realizes it is the same man he spoke to about Hurricane Iris in the coffee shop who promised him he had no idea how bad things would get, the words now beginning to take on a whole new meaning...
Bleary-eyed and drowsy but alive, elderly Evelyn awakes to find Sanchez at her side, having saved her life. Evelyn thanks him, squeezing his hand and smiling up at him.
Meanwhile, the sun has finally come out, Hurricane Iris now past. As Longworth walks the street through the debris, his cell phone rings. It's Manus, with more information on the case. Manus tells him to make sure and thank his confidential source for the information that closed the case just as Longworth turns to see Callie hurrying from the hospital. Manus also informs him that Tommy Owens was recently laid off from the company where Valerie Raines worked and was also turned down from the bank where the loan officer was killed. Not only that, but Owens also suffered from bipolar disorder and was getting electroconvulsive therapy and taking medication, which ran out after he lost his job and insurance.
Longworth adds the evidence up and decides that Owens finding out the son he raised wasn't actually his, losing his job, getting a divorce and being turned down for a loan was just too much for him to handle at once -- a kind of perfect storm. Longworth quickly realizes he has to stop Owens before the man completes the spree killing by murdering the person he feels to have let him down the most: his wife and mother of Peterson's illegitimate son, Tanya Owens. Longworth quickly sends a unit to the killer's apartment as Callie approaches, handing him Owen's file. As Longworth leaves to follow the unit, he finds something in the file that troubles him, making him change his mind about Owen's next victim. He takes a quick scan of the parking lot and he sees what he fears he might, the spot reserved for hospital administrator Carol Watkins left empty, her car nowhere in sight.
On the other side of town, Carol Watkins enters her house to find Tommy Owens pointing a .44 magnum in her face, about to shoot her. Watkins begs Tommy Owens for her life when suddenly Longworth approaches the pair from behind. Longworth plays to Owens' weakness, explaining that everyone he killed had in fact let him down in some way: Valerie Raines fired him, Charles Kendrick denied him a loan, Dennis Peterson slept with his wife and bore her a child and finally Carole Watkins cut him off from insurance and the medication that helped him stay sane. Longworth continues to sympathize, arguing that Carole Watkins is the worst kind of bureaucrat who lives to say "no" to people like Tommy. He tells Tommy to go ahead and shoot her, except of course, if he'd rather have his medication, which Longworth holds out in front of him.
Longworth tells Tommy he wants him to have the medication he so desperately needs and throws the bottle to him. However, what Tommy doesn't know is that Longworth has intentionally left the cap unscrewed and pills go flying everywhere. Tommy dives down to grab for them and Longworth quickly tackles him, wrestling the gun away. And with that, as quickly as it began, the murdering spree is over.
Manus joins Longworth at Tommy Owens' house as the man is carted away in a squad car. Carol approaches them and thanks Longworth for saving her life. She tells him he seemed quite convincing telling Tommy to shot her and questions whether he really would have let him. Longworth replies that maybe the selfish administrator should consider how she treats people and walks away without another word.
At Callie's house, she, Jeff and Longworth clean up the debris that Hurricane Iris left behind. Longworth picks up a mailbox dropped from blocks away and marvels over the power of the hurricane. As they move debris from the yard, the Callie and Longworth share the weight of some heavy tree limbs, finally learning to work together.