In the aftermath of personal tragedy, Wilson resigns from the hospital... and from his friendship with House. Meanwhile, Thirteen struggles with her personal medical problems while helping treat an executive assistant with a similar personality to her own.
An organ donor's organs are responsible for the deaths of several patients, and the team work to save the last two recipients. Meanwhile, House hires a private detective to keep tabs on Wilson.
A painter's undiagnosed illness affects his work, and House and his team must look at the man's paintings to determine what's wrong with him.
While en route to his father's funeral, House must help the team with a differential diagnosis on a young Chinese girl who has collapsed under mysterious circumstances.
Thirteen brings her one-night stand to the hospital after the woman has a seizure. However, the woman admits she slept with Thirteen so she could get to House and have him diagnose her condition. Meanwhile, House continues to pay Lucas to spy on Wilson.
An ailing man suffers from blackouts and sleepwalks, leading the team to wonder if his sleepwalking is a symptom, or how the man is becoming exposed to something else. When the man's daughter grows ill as well, the team must provide a diagnosis before both die. Meanwhile, Cuddy adopts a newborn but when the birth mother displays a rash, she has to make a decision between putting the mother or daughter at risk.
The team must treat an agoraphobic who refuses to leave his house, and have to work around Cuddy, who is less than thrilled at having hospital equipment relocated. Meanwhile, House is plagued by an itch, and Cameron and Chase have relationship issues.
While Foreman takes on a pediatric case on his own, the rest of the team deals with a 16-year-old factory manager and emancipated minor who collapses at work. When Foreman's patient takes a turn for the worse, he's forced to question whether he can deal with the situation on his own, or if he needs House's help.
A man takes over Cuddy's office and holds House, Thirteen, and several patients hostage. His demand? A diagnosis. The man forces Thirteen to act as a guinea pig for his treatments and House has to end the standoff before a SWAT team opens fire.
The team take on the case of a fitness guru on an all-natural diet who collapsed while filming a video. Meanwhile, Foreman conducts Huntington's Disease drug trials and Thirteen signs on as a subject, Cuddy is forced to move into House's office, and Kutner uses House's name to run an online medical-advice website.
House and his team deal with a bullied girl who collapses during her school's Christmas program. Meanwhile, Foreman and Thirteen grow closer during the Huntington's disease drug trials, House gives a patient a gift, the staff wonder who gave House a special gift, and Cuddy gets an unexpected gift.
Thirteen receives treatment by Foreman while taking part in his clinical trial on Huntington's Disease.
The team take on the case of a Special Education teacher who spits up blood and collapses in the middle of class. Meanwhile, Cameron finds herself taking on some of Cuddy's duties, including dealing with House, and Foreman has to make a decision concerning Thirteen's participation in the clinic trials.
A former cancer researcher collapses in the middle of a cooking class, and the team are forced to reevaluate their own lives when they learn she gave up a promising career to seek personal happiness. Meanwhile, Thirteen suffers adverse reactions from the clinical trials, and Cuddy gives House a dose of his own medicine.
House struggles with his own beliefs as he takes on a case of priest with a disturbing past who runs a shelter for homeless people and sees a vision of Jesus.
A patient with both male and female DNA has the team stumped. Meanwhile, House starts acting nicely, raising Cuddy's and Wilson's suspicions that something is terribly wrong.
House and the team take on the case of Nick, a book editor who loses his inhibitions. The team realizes Nick has frontal lobe inhibition, which causes him to speak his mind having no control over what he says and making him just like House. Meanwhile, House suspects Wilson and Taub are keeping something from him.
A nursing home worker, Morgan, fakes an illness to get House to examine a cat which can predict the death of elderly patients. House doesn't believe it... until Morgan becomes ill for real.
House is injured in a motorcycle accident in New York and finds himself in bed next to a patient suffering from complete paralysis. As House transfers the patient to Princeton to determine what's wrong with him, Wilson tries to find out why House was in New York.
The team deals with an older woman who has been tending to her dying husband but is stricken down with an unknown disease that threatens to hug her before her husband.
Cameron and Chase are going on vacation when they meet an enviromentalist who collapses in the middle of a protest. They postpone their vacation and ask House to take on the case.
A deaf 14-year old wrestler suffers from hearing problems during a match, but his mother refuses to okay cochlear implants. Meanwhile, House's insomnia proves a curse... and a blessing.
While House tries to cope with his insomnia, he takes on the case of a ballerina whose skin begins to fall off after treatment following the collapse of her lungs during a performance.
House takes on a case of a patient with two different personalities as a result of having the left and right part of the brain operating independently.