A woman heads out for a day at the beach with her cat, Tizzles, when the animal startles on the way out of their resort condo and runs to an open door down the hall. The woman follows her cat to an unlocked apartment and discovers a trail of rose petals leading to a bed where a man in a kimono lies dead.
Meanwhile Jim Longworth, dressed sloppily for trial, exits the county courthouse with sharp and primped Assistant District Attorney Monica Gentry. They banter for a minute about Jim's casual dress and she's definitely flirting, but as they are in the process of making a date for drinks, Longworth spots Callie exiting another court building and abandons his plans with the DA, too interested in Callie to notice Monica stalking away, thoroughly insulted.
As Longworth approaches Callie, he realizes he has caught her at a bad moment. She tells him her imprisoned husband Ray has not paid their property taxes in three years and she and Jeff are now at risk of losing their home. Just as she shares this news, Longworth gets a phone call from a very shaken Daniel Green, who tells Longworth that Carlos Sanchez has been killed.
Jim hurries to the scene of the crime, takes one look at the deceased and quickly realizes it isn't Carlos Sanchez at all, although the victim was found with Sanchez' driver's license and credit cards. Suddenly, Carlos arrives on the scene, not dead, just showing up late from an American Medical Association luncheon. As they roll the body over to show Sanchez the man they thought was him, they discover three mackerels lying beneath it. Longworth questions whether Carlos knows anyone in the mob, given that a man carrying his identification is now "sleeping with the fishes," and all stand in contemplation of the very real threat against Carlos.
Canvassing the dead man's apartment, Jim finds a photo of two small children which seems to have been purposely removed from a frame on an end table, along with a number of items used to set a romantic mood. Longworth runs the photo of the kids past Carlos, questioning whether he knows them and explaining it's the only personal item he could find in the home. Carlos says he does not.
As Longworth and Sanchez analyze the body, Green arrives with a flyer from the Home Owners Association, found in the mailbox. He tells the men that the president of the association has informed him that the apartment belongs to a Dr. Arthur Kattleman. Longworth wonders aloud as to why a doctor would want to steal another doctor's identity and Sanchez suggests it may have to do with the need for medical malpractice insurance, which makes it easy for doctors to get sued.
The team goes to pay Dr. Kattleman a visit. When questioned about his condo, the doctor explains it's one of nine he owns in the building. Longworth shows Dr. Kattleman a picture of the victim, but the doctor assures them he's never seen the man. He tells them a woman named Ashley Carter is the one who pays the bills for the unit. Longworth and Sanchez speculate that Carter could be the "kept woman" of a mobster. Dr. Kattleman hands over Ashley Carter's credit score and social security number.
Longworth plans to have Manus get Ashley Carter's information to the Records and Identity unit, suggesting maybe the victim and killer were part of a stolen credit card ring. In the meantime, Sanchez has received a positive identification on the victim: his name is Jack Grayson, a county building inspector likely connected with the mob. Nervous about safety given the potential mob involvement, Sanchez phones his wife, asking her to take the kids and go stay with her sister. Longworth decides he will get in touch with an old mobster friend of his to find more details on Grayson.
At Callie's house, county assessor Jason Elkins reviews her property information and determines she owes about sixteen thousand dollars to the government. Callie proposes a payment plan, but Elkins tells her it's not the property tax that concerns him, it's the fact that her income doesn't match her tax filings, specifically her husband's stated income. He tells her that if she has signed tax returns containing false information, she can be held criminally liable and he must take some time to decide whether to refer the matter for prosecution. As Callie's life falls down around her...
Sanchez and Longworth meet with Longworth's mobster friend, Gordon Ganza. They question whether he knows the deceased building inspector, Jack Grayson, explaining that he was carrying Carlos's ID and credit cards when he was murdered, likely by the mob. Ganza explains Grayson was a smalltime player who sometimes turned a blind eye to code violations at one of the new properties he was building on the glades. He also tells them that Grayson had a new lady friend named Bella who was recently keeping him in good spirits. Carlos tries to interject with questions, but it's clear the mobster is not fond of him.
That night, Ashley Carter slips into her building to collect the mail, which is all addressed to various aliases (one of which is Bella DeAngelo). As she checks the mail, Ashley is stopped by Longworth, who has been waiting for her. Longworth questions her about her various aliases and Jack Grayson, who she says is likely to be upstairs watching TV, unaware yet of what has happened to him. Longworth quickly tells her Grayson has been found dead in her apartment earlier that morning.
Shocked by the news, but not grieving, Ashley tells Longworth that Grayson had stayed over the night before but had promised to surprise her when she returned from classes at the University of Central Florida where she is a PhD student. With a little prodding, she explains she and Jack had an "arrangement" and he was helping her pay for school. Longworth questions whether Grayson had a wife and kids and Ashley tells him he is divorced with no children.
Longworth isn't buying it and produces the photo he found in the apartment which had been shoved in a drawer. Ashley claims the children in the picture are her niece and nephew. They talk more about her education and she tells him she's studying Social Anthropology and that her liaison with Grayson is part of an untraditional partnership called The Girlfriend Experience in which she is participating in order to better understand the connection between love and sex in human relationships.
The set-up, Ashley explains, gives individuals the ability to have a relationship with someone you enjoy being with without the complications of a commitment. Furthermore, she continues, the relationship with Grayson was part of her dissertation to understand the way traditional relationships evolve in a society where public space is replaced by cyberspace. The only caveat is that the two men she was conducting research on did not know they were her test subjects. Longworth learns that Grayson was paying Ashley $3,500 a month, but the other subject was the one paying her rent.
As it turns out, this other man is none than Dr. Kattleman, who is giving Ashley free rent in exchange for sex three days a week. Longworth and Sanchez debate the legality of this set-up but determine it's not enough to constitute prostitution and thus they cannot hold her. They question Dr. Kattleman at his sprawling property and accuse him of lying about Ashley and not knowing the dead man. Kattleman tells them he didn't care what Ashley did on the days they weren't together and that truthfully she had the IQ of a walnut. Longworth clues him in on the fact that Ashley was merely playing him, acting the way she thought he wanted her to and using him as the guinea pig for her research. Longworth presses him about his knowledge of Ashley and Kattleman offers that she did text frequently with someone named Professor Landers.
Sanchez moves to join the two and dangles the idea that maybe Kattleman's wife caught on to the affair and would've gotten a cut of his real estate holdings if the two divorced. Kattleman is unfazed.
The next day, Callie speaks to a financial counselor about consolidating her mortgage and opening up a new credit line but has no luck. Jeff enters while she's on the phone, remarking that they never had these kinds of problems when his father was paying the bills. Callie is about to tell him the truth about his father, but quickly stops herself.
At the university office, Longworth talks to Professor Gil Landers, Ashley Carter's frequent text buddy, who tells him that while he signed off on Ashley's project and stayed up to date on her progress, the study itself was blind and so he had no knowledge of the men Ashley selected for it. Longworth suggests that Landers should've advised Ashley against the study, but perhaps he didn't because he was getting off on the subject matter. Landers explains that he doesn't "get off" on the pursuit of higher understanding, adding that he's sure the murder had nothing to do with Ashley's work. Longworth notices a quote by Ashley on one of Gil's book jackets and suggests maybe the two were having an affair, but Gil laughs off the idea, explaining that if he was trying to sleep with a student it wouldn't be a broken down PhD candidate like Ashley.
Back at the station, Green gives Sanchez more details about the mackerel found in bed with the deceased. According to Green, the fish is available at any grocery store, but must be eaten the day it's purchased or else it spoils. He checks and finds over 400 places were carrying this brand of fish on the day of the murder, making it very difficult to track. Manus joins the men and tells Sanchez their fraud detection unit has discovered how his identity was stolen - his 14-year-old daughter used his credit card on dealcarnival.com, a site that they've determined is illegally harvesting credit card numbers and making fake plastic. Manus also brings news that Jack Grayson, the murdered county building inspector, received 10,000 dollars in cash two days before he was murdered. Sanchez speculates that Grayson may have gotten greedy on a payoff for ignoring code violations and threatened to talk if he didn't get more money, resulting in his murder. Manus doesn't buy it, but she agrees to obtain a list of the construction projects Grayson was scheduled to inspect anyway.
Meanwhile, Longworth is at the hospital with Callie, engrossed in his own Girlfriend Experience. As they discuss the case over coffee, Longworth wonders aloud if women who objectify themselves like Ashley ever experience any kind of resulting rage. Callie balks at idea that choosing a specific career option is objectifying oneself and tells Longworth that a woman can separate love from sex just as easily as a man can. Changing topics, they talk about Callie's tax problems and Longworth asks again for her help on the case. She obliges and he questions if using only two subjects in a blind study sounds legitimate, given that Callie has done many of these studies herself. Callie explains she would definitely need at least one more subject for an accurate reading and Longworth ponders this as they finish their coffee.
Later, Longworth pays a visit to Ashley Carter, who is now being evicted from her apartment and has lost six months of research because of the ongoing murder investigation. He has come to drop off the picture of her niece and nephew which had been held as evidence in the case and she regards the image with a mix of emotions.
Longworth also tries to apologize to Ashley for ruining her work, but she does not accept, accusing him of viewing her efforts to try and free people from loveless empty relationships as some kind of joke. The balance between love and sex, she explains, is a mysterious one and the ability to find someone who satisfies both drives is what everyone longs for and what she is trying to help people achieve through her research. Longworth apologizes for belittling her work, but maintains that he does not think she is the kind of woman who can have sex with her subjects and not feel anything. To prove it, he tells her he made a few calls and knows that she does not have a niece and nephew. Furthermore, he knows her study requires more people than she's admitting to and demands she tell him who she is protecting.
That person seems to be Colonel Richard Slayton, an astronaut recently chosen as a mission specialist for an upcoming shuttle flight. Longworth approaches Slayton at a NASA administration building and threatens to arrest him for the murder of Jack Grayson if he doesn't start talking. At Slayton's office, Longworth spots an identical photograph of two children that Ashley Grayson had in her home, next to another of the same children in the laps of their parents, Slayton and his wife Debra. Slayton tells Longworth that the situation between he and Ashley is purely about sex and while his wife is not aware of the relationship, he can't risk a scandal when so many other mission specialists are competing for his spot on the space flight. Longworth antagonizes him, calling him a sick bastard for keeping a picture of his children at his lover's house and mocking his admiration for Ashley's work. The latter pushes him too far and he lashes out at Longworth, confirming the detective's suspicions that he is actually in love with Ashley. Slayton argues that his wife is a project manager and treats him like a project, a trait he simply can't handle. Just then, Slayton's wife, a fellow employee, enters, speaking to him in the same way he's just described. It's clear that this is simply another loveless marriage just like the kind Ashley wants to save.
At the bar, Callie meets with Peter Frost, a sleazy lawyer for her and her husband, who tells her she legally committed fraud and is subject to a forensic accounting of all her finances, going back as far as the IRS determines. This is not an option for Callie, given her husband's dirty business dealings, and she tells him she cannot go to jail as she has Jeff to consider. Peter suggests he could quietly work with her husband Ray to make the problem go away, but Callie is not having any of it, and quickly exits.
Longworth and Sanchez head over to the only construction site Grayson didn't inspect before he was killed. At the site, the men meet with Mike Grogan, a project manager on the building and accuse him of offing Grayson when the inspector demanded more bribe money then he could afford. Grogan tells them he's building a senior living center and he could've easily brought everything up to code with the 10,000 he supposively paid Grayson, but he thinks he knows someone who had a real beef with the building inspector. He tells the men he saw Grayson arguing with someone the last time he was by the construction site and shows them video footage of Grayson in a scuffle with none other than Professor Landers.
Professor Landers is interrogated by Longworth, who has gotten a hold of his notes on The Girlfriend Experience and is paging through the clinical albeit sordid details. Longworth suggests Landers killed Jack Grayson when he realized Ashley was falling for him and he would loose his chance at any kind of a serious relationship with her. As proof of his theory, Longworth explains he knows about Landers doctoral thesis "Bonding Rituals and Behavior in Organized Crime Culture" which would explain the fish found with Grayson's dead body. Lander counters that he only spoke to Grayson to let him know his feelings would jeopardize Ashley's research and provdes an alibi for the time of the murder - he was lecturing to 200 undergrads in one of his classes.
Callie gets a text from county assessor Jason Elkins to meet him at a romantic upscale restaurant. When she arrives, she takes in the scene, the wine and low lights, and is concerned about what Elkins has really brought her here for. Elkins tells her he can make her tax problem go away as long as she makes restitution to her penalties and principal in a timely fashion, but Callie can see he's after more. She leaves the restaurant and the slimy Elkins without another word.
Longworth returns to Ashley's to review the crime scene. He considers two DVD players he finds, realizing there are no DVDs anywhere in the apartment. Suddenly he hears someone entering the apartment and draws his gun. He and the man pause in a Mexican standoff as Longworth realizes the shadowy figure is Dr. Kattleman. Kattleman says he has come to take inventory of the place so that he can lease it to a new tenant as soon as possible. Longworth questions Kattleman about the empty DVD players and takes Kattleman's gun to determine if it's the same one that killed Grayson. After the doctor exits, Longworth ponders the DVD players, formulating a theory, and phones Green to have him verify it...
Later, Manus and Longworth sip coffee at the station and catch up on the case. Manus tells Longworth that the day Grayson made a deposit for 10,000 dollars Colonel Slayton made a 10,000 dollar withdrawal. Just then, Green arrives to let Longworth know his theory was correct: Slayton's Netflix queue is loaded with mob movies. Finally, the mackerel seems to make sense. Longworth puts together the pieces concluding Jack Grayson was blackmailing Slayton (Ashley's third subject), giving him a perfect excuse to off the building inspector and staging it to look like one of the mob killings he saw in his favorite films.
Slayton sits across from Longworth at NASA, pleading that if he does not get on this shuttle flight, his whole career has been for nothing. He explains this is the reason he paid Grayson 10,000 dollars to keep his mouth shut, but he claims he never Netflixed mob movies and only rented date films with Ashley. He also assures Longworth that while he was sometimes jealous of his girlfriend's other affairs, he knew her research was coming to an end and was planning to divorce his wife anyway. Their conversation is cut short when Longworth's cell phone rings. It's Green, who has finally found the shop where the mackerel came from and plans to get security footage to find out who bought it. Longworth stares at the family photo of Slayton with his wife and kids, forming one final conclusion. His mind made up, he tells Daniel there is no need to get the tape, he believes he now knows for sure who the murderer is.
Debra Slayton, Colonel Slayton's wife, is in her NASA office when Longworth busts in. Longworth confronts her, knowing now that she was the one who actually committed the murder because it threatened her picture perfect family. Realizing she's caught, Debra admits that she went to Ashley's apartment to scare the girl and was shocked to find the picture of her children on the table when she arrived. Then a man came out the bathroom and threw her on the bed (thinking she was Ashley) and she accidentally shot him and planted the fish to make the crime look like a mob hit. Taking pity on her, Longworth tries to sympathize with her relationship struggles and give her advice, but it's clear this woman and her flawed marriage clearly could've benefited from Ashley's research.
The case solved and the murder weapon given up by Debra Slayton, Longworth returns to the station, letting Manus know that Colonel Slayton will get to keep his seat on the shuttle and Ashley can go back to her research.
Callie has Elkins over her house for dinner to apologize for her behavior at the restaurant. Thinking he has the upper hand, he tells her that if she sleeps with him, he won't turn her case over to prosecution. What he doesn't realize is that she's recorded their whole conversation and when she plays back for him, Elkins lunges at her. Thinking fast, Callie kicks him between the legs and out of her house.
At Longworth's, Callie's son Jeff mimics Scarface by the pool as Callie arrives, letting them both know that her payment plan has been accepted and the matter is closed. She asks Longworth about his own matter and he tells her the Girlfriend Experience case is also closed, thanks to her help. Without her, he says, he wouldn't have been able to realize a detached woman is capable of falling in love. By this logic, he argues, a woman in love might also be permitted a little detachment sometimes. He's talking about her and she knows it. The moment is heavy and filled with innuendo as Callie exits with Jeff, smiling sweetly at Longworth as she departs.