Zach loops Alex on the case of Carlos Garcia, who got sick on a plane, prompting an emergency landing. Luckily, fellow passenger Dr. Mark Wilson has accompanied Garcia to Hope Zion, fearing a ruptured appendix. Garcia thinks he just has a bad chest cold. Prescribing an IV, Alex guesses Wilson's diagnosis is probably correct, but she schedules surgery right away to be sure. Afterwards, Alex meets Melanda in the ICU to explain her new treatment schedule for Charlie: transcranial magnetic stimulation, which delivers alternating, pulsating electromagnetic fields to the prefrontal cortex. It might just wake him up... or he could have a seizure. When Victor starts bickering while hooking up the machine, Shahir explains they're having a disagreement. Shahir's mother is in town, and after two years of dating, he didn't tell Victor, who's never met her. Shahir doesn't think it's a big deal, but Victor definitely does.
Maggie spies Gavin flirting with another young doctor named Hannah, and can't help raising an eyebrow. When she tells Gavin that she's happy he's seeing someone, he claims they're just friends. Maggie proceeds to check on patient Carol, who's so nervous about her upcoming spinal decompression surgery that she's started superstitiously looking to numbers for luck. When Joel steps in to consult, she asks him to repeat the words "surgery" and "pain" three times every time he utters them. Afterwards, when Maggie asks Joel what they're doing this weekend, he criticizes her work, then abruptly begs out of the date. Meanwhile, Alex scrubs for surgery with Dr. Rachel Pratt. Though Garcia's ultrasound was murky, Pratt thinks his surgery will be a piece of cake. Joel pulls Alex aside to apologize for being weird; he wants to be friends again. Pratt has difficulty intubating Garcia, causing him to cough repeatedly.
Once Garcia is open, Alex is stunned to find that his appendix is perfectly fine. So what's causing his abdominal pain? Suddenly, Garcia starts crashing, then coding. Alex, Victor and Pratt struggle to do everything they can, but within minutes, a shocked Alex is calling time of death. Afterwards, Alex recounts what happened to Kinney and Zach, who suggests that Garcia may have had an aggressive bacterial pneumonia. Meanwhile, Shahir's ready to start Charlie's magnetic stimulation machine. When she learns Charlie could possibly wake up right now, Melanda asks him to wait for Alex, but Shahir's not having it. Sadly, Charlie remains unresponsive to the stimulation, and neither of them have any idea whether the machine is doing its job. Nevertheless, in a few moments, a disoriented Charlie finds himself standing on the street in his tux with a bleeding cut on his forehead. "This can't be real..." he says.
Alex examines Dr. Wilson. On the plane, Garcia told Wilson about his cold, and was experiencing shortness of breath, abdominal cramping and fever. Wilson is surprised to learn that he has a fever of 102 along with wheezing, so Alex orders a chest x-ray. Zach calls Alex out of the room to report that Garcia flew out of Mumbai yesterday, transferring in Frankfurt... and the WHO just identified a cluster of coronavirus (like SARS) in a village just outside Mumbai. Alex dons a mask, and tells Wilson about the virus; they're going to isolate him for now. Meanwhile, Maggie assists Joel with Carol's surgery. He drills her on procedure and refuses to laugh at her jokes. Clearly, something's not right with Joel.
Shahir chases down Victor in the hallway to explain that the reason he hasn't asked him to meet his mother isn't because Victor is gay... but because he's a nurse! Shahir's mother always wanted her son to marry a doctor or architect. Assuming Shahir is ashamed of him because he's a nurse, Victor calls him pathetic and stalks off. Alex meets with Kinney and hospital administrator Bryan Travers to ask them to lock down the hospital - now. Kinney concurs, but Bryan wants to avoid negative press. Alex points out that right now, they can still contain the risk, but Bryan insists on keeping Hope Zion's doors open. Meanwhile, Wilson's condition has deteriorated wildly, and he knows it's not just the flu.
It's not long before infectious disease expert Dr. Peter Hibbs is meeting with Kinney, Alex and Bryan. Already well versed in coronavirus symptoms, he offers the worst-case scenario: of the hospital staff and patients could be dead within 12 to 24 hours. And since the virus is highly adaptable... well, all bets could be off. Kinney asks him to keep this information under wraps; they're not using the word "virus" just yet. Hibbs dons a hazmat suit to inspect the ICU, as Alex tells Melanda that until the virus question is settled, no one goes through Charlie's door. In the meantime, his electromagnetic treatment will continue, since it can't hurt - while the virus could totally kill him. Meanwhile Charlie is disappointed to learn that the people around him on the street still can't see him. He stumbles across two dead people in a crashed car and freaks out - they're his parents!
Maggie complains to Joel that the hospital has fallen into chaos since Bryan has cancelled all surgeries. When Joel refuses her request for help and calls Maggie by her last name, she asks what's going on, but he just walks away. Maggie checks on Carol, with news that her surgery went well. In fact, had it been scheduled an hour later, her surgery wouldn't have happened at all. When Carol asks why, Maggie distractedly mentions the virus, then backpedals, saying Carol wasn't exposed. Chaos reigns in the hospital lobby, where Reycraft spies Dr. Pratt coughing, then falling to the floor in mid-seizure. Moments later, Hibbs pages Joel, Alex and Victor to the OR to tell them that they've quarantined Pratt since she's showing symptoms of the virus. Since the three of them were in the OR with her, they're under quarantine too.
Down in the ER, Zach finally lets the cat out of the bag, announcing to all that the hospital is going into temporary lockdown because of the virus. Reycraft steps up to inform that anyone who came into contact with Garcia is going into isolation, including Zach. Meanwhile, Victor discovers that he has symptoms - what if this is it, and they're all about to die!? Shahir returns to the hospital, stunned when cops refuse to let him back inside, regardless of the fact that Victor is sick. Meanwhile, Carol plunges headlong into her numerical neurosis, which Gavin identifies as the Law of Contagion, a form of magical thinking. Realizing Maggie is exhausted and overworked, Gavin urges her to take a break, just as Kinney announces over the PA that Hope Zion is under quarantine. All movement is fully restricted; everyone must stay where they are, and no one is permitted to touch anyone else.
As Victor's symptoms worsen, he worries about Shahir, whom he can't reach on the phone to apologize for their fight. Rather than expose Alex and Joel to the coronavirus, Victor takes himself into the OR and lies down on the operating table. Alex worries aloud over Charlie, then realizes that Joel has shown no concern for Maggie whatsoever and hasn't talked to her. Alex knows this means Joel has been cheating on Maggie, since he did the same thing to her. When Alex admits this is none of her business, Joel admits he doesn't feel bad about cheating anyway. Meanwhile, Maggie and Gavin are stuck in Carol's room. Gavin tells Maggie that he wishes he could take back the kiss, and she apologizes for behaving badly. Since it's 2:00 a.m., the two of them decide to share the second bed in Carol's room and sleep holding hands.
When an alarm sounds in Wilson's room, Melanda and Jackson rush in to save his life, but he dies in his bed. Meanwhile, the discussion about Joel cheating on Maggie has grown more heated. When Joel accuses Alex of walking out on him, she angrily explains that she left because he cheated on her and broke her heart. The truth is he's not the kind of guy who will risk his heart - for anyone. When Joel leans in for a kiss, Alex slaps him - hard. Just then, Melanda calls to report Wilson's death. Alex looks up to spy Victor coughing in the OR. Melanda promises to send down a team, as Alex and Joel don masks and rush to get Victor some oxygen.
Charlie sits in the wrecked car with the bloody corpses of his parents. He never pictured their accident like this. And usually dead people talk to him - why won't they? When Charlie angrily demands they open up, he's transported into the past, to re-experience the night of his parents' fatal car accident. The shock of the crash sends his eyes flying open with a spasm of movement, as alarms ring through the ICU. But they're not Charlie's alarms - they're Pratt's. Within minutes, Pratt is felled by the deadly coronavirus. Hibbs tells Kinney that the WHO has delivered test results on the Mumbai cluster of the virus, concluding that the incubation window is 12 hours, and it only transmits through large droplets with no secondary transmissions. They're free to open the hospital doors.
It's morning by the time the hospital doors open. Reycraft releases Alex and Joel from quarantine, as Shahir rushes to Victor's bedside. Luckily his fever is coming down. Victor apologizes for their fight, and Shahir finally tells Victor that he loves him - clearly, it's the first time he's said these words. Maggie tells Carol that she's in the clear, then introduces her to Gavin, in hopes of finding help for her numbers obsession. After work, Joel finds Maggie sitting on a bench outside. Maggie asks to speak first: Joel's a terrible boyfriend, and she can do so much better. Joel agrees and apologizes, but it's definitely over.
After her shift, Alex calls for Melanda as she enters Charlie's room, shocked to see his arm over his head. Melanda insists the room has been sealed throughout the quarantine until just now, and there's nothing on the EEG tape. Concluding that Charlie didn't have a seizure, Melanda rushes off to page Shahir, as Alex glories in the fact that Charlie moved. Charlie tries to tell Alex about his revelation of the last several hours, the memory he has buried all these years: he was in the car and saw his parents die. Unfortunately, he fails to tell her anything, because he's still comatose...