House insists he can handle things when Stacy, the woman he once loved, asks him to diagnose her husband, Mark. But despite Mark's tests coming back normal, his steadily growing symptoms indicate he is dying. While House struggles with the mystery and makes increasing demands on his staff, Wilson worries about House's emotional well-being. Working to save Mark, House cannot help but think his feelings for Stacy may have reignited. Cuddy considers hiring Stacy if House agrees; he does.

House's ex-girlfriend and former hospital legal counsel Stacy Warner returns not to be with House but to get his help diagnosing her ailing husband. While House decides whether or not to take the case, Cuddy forces him to substitute for a sick professor and present a lecture to a class of medical students. As he interweaves the stories of three patients who present with a similar symptom, House gives a lesson the students will never forget.

House apparently scares a meek clinic patient into having a stroke. The team must deal with the patient's odd lifestyle, overbearing "friend," and reluctant parents to stop the strokes and try to save his life. But the major topic of discussion is House's imminent date with Cameron, which is her condition for accepting House's rehire offer. Meanwhile, Wilson, Cuddy, and the team offer House and Cameron advice while laying odds on the outcome.

During a meningitis outbreak that overwhelms the resources and staff of Princeton-Plainsboro Teaching Hospital, House singles out a 12-year-old patient whose symptoms are similar to but not quite right for the disease. House, Foreman, and Chase must devise ingenious ways and locations to treat the girl's delicate condition in the middle of the chaos and make an unexpected discovery. Meanwhile, House asks Cameron to come back to her job, but she has one requirement that he might not be able to meet.

While House and his team scramble to discover what's causing brain and kidney dysfunction in a pregnant woman, Vogler is on the warpath to get House fired after House's pharmaceutical speech. House determines the illness, but the woman and her husband struggle with an emotional and heartbreaking choice between her or her unborn child. Vogler calls for a vote of the Board of Directors to remove House, but when Wilson refuses to make the vote unanimous, Vogler threatens to take his money if the Board doesn't remove Wilson. Finally, Cuddy must take a stand against Vogler.

At a high-level campaign fundraiser, up-and-coming Senator Tom Wright becomes violently ill. Vogler pushes House to take Wright's case and dangles a new incentive in front of him: deliver a speech on behalf of Vogler's pharmaceutical company and save his whole team without firing one. House examines the senator finding that the symptoms point toward AIDS, a condition that would squash his career and presidential aspirations. But House refuses to settle for the easy answer. And House ends up giving the speech, but it doesn't go quite as Vogler planned.

House must fire one of his doctors at Vogler's insistence and leaves them wondering about it while dealing with a case. House and his team blame an adverse reaction to diet pills after an obese 10-year-old girl has a heart attack, but they ultimately uncover a much more deadly source for her illness. House examines a woman who won't accept surgery for a 30 lb. tumor because she wants to remain overweight.

Just before mobster Joey Arnello spills the beans in federal court and enters witness protection, he collapses. Is he faking? A court order instructs House to find out - and fast. House and his team struggle to diagnose and cure Joey while Joey's brother Bill tries to slow things down and keep Joey from testifying. Meanwhile, Cuddy struggles to convince Vogler that House is an essential part of the hospital.

Billionaire entrepreneur Edward Vogler spends $100 million on Princeton-Plainsboro Teaching Hospital and becomes the new Chairman of the Board. As a businessman, Vogler intends to turn the clinic into a profitable venue for his new biotech venture and plans to eliminate the financially draining services of Dr. House. Meanwhile, a businesswoman who has it all - perfect life, perfect body, perfect job - is inexplicably paralyzed. When he diagnoses her secret, House must risk his career and medical license to get her a necessary transplant.

A 12-year-old boy believes he's cursed after a Ouija board tells him he's going to die. His father, a major financial supporter of the hospital, makes escalating demands of House and the team as they try to diagnose the boy's pneumonia-like symptoms and incongruous rash. Meanwhile, Chase's estranged father, a renowned doctor from Australia, visits, and House invites him to sit in, much to Chase's discomfort. When House diagnoses the boy's illness, the young patient is forced to face the idea that his father may not be everything he believes.

A severely broken arm reveals a bizarre case of bone loss and ends the comeback plans of major league pitcher Hank Wiggen. House suspects Hank is lying about using steroids as his condition worsens. When Hank's kidneys start to fail, his wife offers to donate hers, but she would have to abort her early pregnancy. Forced into an impossible solution and admitting failure as an addict, Hank tries to take his own life. House and his team must soon isolate and fix the problem if this pitcher's life and career can be saved. Meanwhile, Foreman dates a pharmaceutical representative, and House is stuck with two tickets and goes on a "date" with Cameron to a monster truck rally.

House has to determine why a young patient has internal bleeding after a car crash. In the meantime, he takes Cuddy's challenge to stop taking Vicodin for a week in exchange for no clinic duty for a month. But the team thinks House's withdrawal symptoms affect his judgment in analyzing the young man's unexplained blood loss.

Dr. Foreman believes an uncooperative homeless woman is faking seizures to get a free meal ticket at the teaching hospital. But her homelessness strikes a personal chord with Dr. Wilson, and he grows determined to keep her from falling between the cracks. Her worsening symptoms prove to be a complex mystery for House and his team, but the mystery of her identity and medical history may hold the answers to saving her life. Just as the team suspects she has contagious meningitis, the woman goes missing, only to be tasered by the police, who bring her back. But House deduces the taser may have proven yet another diagnosis, with dire results. Meanwhile, House has an audience of two medical students who are learning how to do case studies.

Legendary jazz musician John Henry Giles checks into Princeton Plainsboro Teaching Hospital believing he's dying from ALS and signs a DNR to avoid a slow death. House disagrees with the diagnosis and goes against everyone's wishes when he violates the DNR to save Giles' life. The decision lands House in court, drives Foreman to consider taking another job, and results in Giles' paralysis worsening. But when the patient inexplicably starts getting better, the team has to figure out the mystery in reverse and find out why his condition is improving.

When a high school student falls victim to a mysterious but lethal poisoning, House and his team investigate what is killing the teen. Suddenly, a second unrelated student is admitted with identical symptoms. With the boys' lives hanging in the balance, House and the team have to connect the dots fast. Meanwhile, an 82-year-old patient has become enamored with House while he helps her figure out the basis of her renewed fascination with her sexual feelings.

After Ed Snow discovers his wife Elyse constantly sleeping for several days, she is admitted to the hospital. Dr. Cameron is very interested in the case. So much so that her interest convinces House to take the case. The doctors are puzzled by her symptoms, considering everything from tumors to breast cancer to rabbit fever. When all the treatments fail, House concludes she has African sleeping sickness contracted through sexual intercourse. However, neither Elyse nor Ed has ever been to Africa. Neither one will admit to having an affair. She will die without the proper treatment.

While dodging Cuddy in the emergency room, House runs into the son of a schizophrenic woman diagnosed with alcoholism. Intrigued by her schizophrenia and the fact she has deadly deep vein thrombosis, a condition she's too young to get, he takes her case and finds multiple problems. However, when the patient does something unexpected, House starts to wonder if she's mentally ill at all.

When a nun comes into the clinic with swollen arms, rash, and bleeding in her palms, Dr. House's diagnosis is a bad allergy, not stigmata as she believes. House gives her an antihistamine which appears to set off an allergic attack. However, when the nun gets tachycardia from the epinephrine House gives her to treat it, Cuddy concludes he gave her ten times the appropriate dose. When House insists he gave her the proper dose, Cuddy gives him 24 hours to prove the nun has another condition before she calls the malpractice lawyers. Although House finally vindicates himself, the answer doesn't help the patient. As her condition worsens, her fellow sisters pray for her while House and his team work to discover the cause of her illness. House wonders if he misdiagnosed her situation, not realizing that her past is coming back to haunt her.

Dr. House exasperates his boss, Dr. Lisa Cuddy, when he suggests that two sick newborn babies in one hospital add up to an epidemic from a spreading virus. Even more frightening is that he may be right as four more babies fall ill, the maternity ward closes, and the doctors battle over courses of treatment. House and his team must make decisions that could compromise the babies' lives.

A college student collapses after rowdy sex with his girlfriend. While House and his team attempt to determine the cause, the student's condition continues to deteriorate, and his symptoms multiply, complicating the diagnosis.

When a teenage lacrosse player is stricken with an unidentifiable brain disease, Dr. House and the team hustle to give his parents answers. Chase breaks the bad news that the kid has multiple sclerosis, but the boy's night-terror hallucinations disprove the diagnosis and send House and his team back to square one. As the boy's health deteriorates, House's side-bet on the paternity of the patient infuriates Dr. Cuddy and the teenager's parents but may just pay off in spades.
 

Dr. Gregory House and his team take medical cases only after everyone else has failed to diagnose a patient. A Kindergarten teacher begins speaking gibberish and passes out in front of her class. What looks like a possible brain tumor does not respond to treatment and provides many more questions than answers for House and his team as they engage in a risky trial-and-error approach to her case. When the young teacher refuses any additional variations of treatment and her life starts slipping away, House must act against his code of conduct and make a personal visit to his patient to convince her to trust him one last time.