Taub and the team treat a depressed patient who reminds Taub of himself a lot this week. When a homemade tape that depicts an explosive is found, along with a yearbook that bashes pretty much everyone in his class, Taub makes the choice to tell the police about the teenage boy.
But the real heart of the episode lies in the fact that a lump is discovered in Cuddy's kidney.
House is at first in denial, refusing to even visit Cuddy as she awaits surgery that will remove the lump and determine if it's cancerous. Throughout the hour, we get treated to a series of unique fantasies and spoofs - zombies, lame sitcoms, etc. - that depict the different possible states of Huddy and how Cuddy envisions these two ending up.
After she gets the surgery and learns the tumor is benign, all seems right in the House world. Until she realizes that House was on Vicodin when he visited her. He wanted to numb himself from pain, which is a selfish trait and not the sign of someone really willing to get dirty in a relationship, considering pain will also be a possibility.
As a result, Cuddy breaks up with House because she doesn't think he can change.