Drug dealers Mickey and Eddie conduct a deal from the back of a car. When a gun shot rings out, Mickey drops to the ground. He is unhurt but unconscious. At the hospital, House tends to Mickey's head wound and knows something is a little shady with these guys. They want to hightail it out of there, but House figures something is really wrong with Mickey. He slams his cane with a thud and Mickey passes out. House discusses the case with the team. His vertigo is loud noise-induced but the head is free of internal damage. Foreman suggests acoustic neuroma but House thinks it could be poisoning from cocaine.
Wilson chats with his neighbor, Nora, in the lobby of his new building and asks her to dinner. She suggests they bring House along.
Taub and Foreman check Mickey's hearing. Foreman shows to Taub a paycheck stub of Thirteen's. He learns that she and Taub make more money than he does. Meanwhile, House tries to interrogate Eddie to get a sample of the cocaine. He is interrupted by Wilson, who says that Nora thinks they are a gay couple.
Mickey convulses during the hearing test. Taub thinks it must be his blood pressure. The team gathers and Foreman notices that Thirteen has a new pricey watch. With the hypertension under control, Thirteen suggests that perhaps Mickey's carotid arteries are clogged.
Foreman asks Cuddy for a raise and she tells him he will have to wait. Taub and Thirteen report back to House that the patient's arteries are clear. House fiddles with a wideband receiver used to bug Mickey's hospital room. He wants to locate where the drugs are hidden. House thinks toxic exposure is the reason that Mickey is sick. Taub tries to keep Mickey in the hospital but he demands to be discharged. Thirteen and Chase tail Mickey's car. They have been playing a trick on Foreman with the paycheck and watch. Thirteen runs a red light and the cops catch her.
House meets Nora in the apartment lobby. As he assures her that he and Wilson are straight, a delivery comes -- it is a giant poster of musical "A Chorus Line." House asks Nora to help him upstairs with it. Later, Wilson confronts him about Nora. House is also interested in her. He is keeping up the charade of being gay to get close to her.
Mickey is back in the hospital with a high fever. Chase and Taub take a lumbar puncture from the patient's back. Mickey knew that he was being followed. His heartbeat is normal when it should be fast. He has been taking beta-blocker pills to calm his nerves and keep his heart rate regulated. House orders an MRI of the adrenal glands to check for Pheochromocytoma.
Wilson comes home to find House massaging Nora with a Chinese take out spread on the floor. Nora asks Wilson to join them. He does so awkwardly. Later on, Wilson insists to Nora that he is not gay. She thinks he is merely jealous of her.
While Taub and Foreman run an MRI on the patient, Foreman admits that he lied to Cuddy about a job offer in order to leverage a raise. Cuddy told him to take the other job. Foreman plans to quit after this case. The MRI comes back negative.
House comes to Mickey's room and asks him why he was on beta-blockers that only reduce the symptoms of stress. House pulls his bug from the bed, but finds one that Mickey hid. House realizes that Mickey is actually an undercover cop. He has been working the case of a top drug dealer and tomorrow would be the bust. Eddie enters and Mickey suddenly gasps for air. He has a GI infarction caused by a clot in his superior mesenteric artery.
Thirteen tries to convince Eddie to tell her where the cocaine is located by drugging his coffee. Eddie takes her to a dry cleaner store where Mickey has been living. Someone comes in and they pretend that she is a hooker.
House is out to dinner with Nora. He is making his move on her when Wilson comes in and proposes marriage to House. He's speechless.
Chase, Taub and Thirteen run various tests on the samples that Thirteen brought back from the cocaine stash. Mickey starts coughing up blood. It's not the dry cleaners because they aren't using toxic chemicals. Chase explains to the team that Mickey has a series of aneurysms in his lungs. Foreman will put him on antifungal medication in case it is a fungus. Eddie and Mickey share a moment before Eddie unknowingly heads off to be busted by the cops at the drug deal.
Chase, Taub and Thirteen confess to Cuddy about their prank and plead for her to reinstate Foreman. They offer to skim from their salaries to add to his. Cuddy agrees, but says she hasn't seen Foreman in days. The three walk out to find Foreman waiting for them and smirking.
Nora comes by the office to see House. He admits his plan to her and tells her that Wilson is a good guy. House rushes to Mickey's bed because he realizes that the aneurysms are inflammatory and not fungal, as they had originally thought. Mickey suffers from Hughes-Stovin, an untreatable autoimmune disease. The sting operation goes forward while Mickey prepares to die in his hospital bed. House compliments Foreman on playing the other three so well.
In their condo, House and Wilson watch TV on new recliners that House has purchased. Wilson threatens to sing "A Chorus Line" tunes until House gets rid of them.