House and the team are intrigued by Scott (Ashton Holmes), a man who has undergone a corpus callosotomy procedure to treat epilepsy.
As the two sides of Scott's brain struggle for dominance, his warring personalities make it increasingly difficult for the team to figure out what is causing the problem.
When, as part of this plan, House refuses to make his scheduled appearances in the clinic, Cuddy begins referring patients to see House in his private office, specifically an annoying elderly man named Eugene Schwartz (guest star Carl Reiner) whose wife is bothered by the odd "squawking" noises he makes.
To Chase's complaints about his relationship crisis with Cameron, Taub responds by talking about toxic chemicals of male fruit flies.
In a final attempt to provoke Cuddy into examining her true feelings for him, House announces to everyone in the main lobby of the hospital that the two had sex.
At the same time, it is reported that the patient with alien hand syndrome, Scott, is really suffering from a reaction to an ingredient in the industrial-strength antiperspirant he uses.
He asks Cuddy whether she has another type of lipstick that might explain the discrepancy between his memory of the smeared kiss and the reality that now confronts him of the unsmeared coffee cup.
The whole previous night was a complete hallucination, beginning from him telling Cuddy that he needed her to help him detox and her accompanying him home.
The last scene cross cuts between shots of Cameron and Chase's wedding and Wilson driving House to Mayfield Psychiatric Hospital.