A couple named Julia and Damian are enjoying a romantic rendezvous in a hotel room when there is a knock on the door. It is Julia's husband Tom with some papers to sign for their child. Tom doesn't seem fazed by the sight of his wife with another man and is actually apologetic. Suddenly, Julia clutches her stomach in pain. Damien runs to find Tom for help.
After Sam leaves Wilson's condo, House once again tries to get Wilson to see that this relationship won't be any better the second time by pointing out the things that still annoy him. Wilson refuses to listen.
At the hospital, the team tells House about Julia's case, including the part about the open marriage. House does not find this interesting because he believes that people are not meant to be monogamous. Julia has an intestinal blockage that Chase suggests may be from Herpes colitis. A barium enema will diagnose it, which House will perform himself in order to meet the patient. Julia tries to defend her lifestyle choices to him.
Taub flirts with a physical therapist named Maya in the hallway. Thirteen takes note. Taub denies anything is between them, explaining that they are just friends like he and Thirteen are friends. They report back to House that the x-ray is clean, so Julia does not have herpes. In fact, her pain subsided during the x-ray. House orders Taub to x-ray her entire GI track, which will take all night.
As he cleans his kitchen with Sam after the work day, Wilson notices she left something in the refrigerator and this annoys him. Meanwhile, Taub administers the x-rays to Julia and asks about her marriage. Taub insists that there are happy monogamous couples out there. Julia's heart races and Taub calls for a crash cart.
Chase asks Tom for a list of his sexual partners because Julia likely has a parasitic infection. Tom says he didn't leave the country, but only went to Nebraska. He confesses that he is not sleeping with anyone and that his wife thinks otherwise. Tom merely needs Julia. She enjoys the open marriage, not him.
House thinks Tom must be doing something to even the score behind Julia's back. Men, according to House, are engineered to be jealous. House sends Thirteen and Chase to snoop around Tom and Julia's home. They find that Tom really did go to Nebraska. Thirteen tells Chase the story of her own father's infidelity. She notices a damp loofa sponge hanging in the bathroom that could contain parasites.
Over dinner that night, Taub tells his wife Rachel about his patient with the open marriage. He also notes that there is a woman at work he likes. Rachel harps on the open marriage thing, but Taub protests that he only trying to be honest. Taub is paged because Julia can't move her legs.
The next day, Taub reports to the team that they found no spinal cord or cerebral injuries. The loofa is also free of parasites. Taub blames House for pushing him to bring up the topic of open marriage to his wife. Julia's need for sex could be an indication of adrenalcortical carcinoma. House orders an MRI of her adrenal glands.
Back at the condo, Wilson mentions to Sam all the things she has done around the house that bother him. When Sam says she's not responsible for those things, Wilson realizes that House did them in order to cause them to fight. Yet Wilson's airing of these grievances exposes the same issues he had before. They argue about his never telling her these things when they were married and what caused their divorce.
Damien brings Julia flowers in front of her daughter and Tom flips out at him for invading on their family. Wilson and Sam argue. Later, Taub and Thirteen administer the MRI to Julia and they discuss his marriage. Thirteen thinks Taub is predisposed to cheating, but he insists he will fight the urge. They do not see anything in Julia's adrenal gland, but find a blood clot on her lung. House thinks a clotting disorder would explain all the symptoms.
Cuddy comes into the office to inform them that Julia's health insurance has not been paid. House jumps on this and goes to the patient's room. This is what Tom has been hiding from Julia. Tom admits that he lost all their savings in a business venture. Julia is mad at Tom for withholding the truth about the money.
Wilson is furious with House because Sam ended their relationship. He wishes House would have stayed out of it.
Thirteen mentions to Cuddy that she thinks Cuddy can do better than Lucas. Cuddy says she is happy and that it is her private business. Meanwhile, Taub comes home and his wife gives him permission to sleep with other women on Thursday nights. Rachel knows that he wants more than just her.
House and the team discuss the case. Julia does not have a clotting disorder. Taub enters and House can tell that his wife gave him permission for an open marriage. Taub plans to take Maya out. Suddenly, everyone's pagers go off. Julia is suffering from the same stomach pain that brought her to the hospital. The team tries to figure out a connection between the two times it occurred. Chase suggests that the pain could have been triggered by the parasympathetic nervous system. Taub takes this idea further, saying maybe it is more important when the pain stopped, rather than started. The barium enema that House gave her would treat an intussusception, where here intestine folded on itself and cut off blood flow. Usually, this is a sign of abdominal cancer.
Julia is rushed to the ER for surgery on the intestine. She does not want her husband there. Cuddy walks into her office to find House brewing espresso on a new machine. He tells her that he realizes that if he does nice things, such as "helping" Wilson end his relationship, then nice things will happen to him -- such as Lucas dying.
During Julia's operation, the team grills Taub about what his wife is up to that night while he is with Maya. They find a lesion in Julia's bowels, but no tumors. Her kidneys are also declining in function. House says that BID makes sense since it can trigger ankylosing spondylitis.
Taub walks to his car in the parking lot and finds a crying Rachel there waiting for him. She cannot agree to the plan anymore. Taub hugs her and assures her he doesn't want anyone else.
Julia's health is failing. Her kidney biopsy showed she had IgA nephropathy. Chase shows the team a list of forty diseases that can be associated with it. House chooses three of the ailments to treat Julia for: Weil's syndrome, sarcoidosis and hemochromatosis.
Thirteen lets Julia know that her husband has been faithful for a year. As Tom sits vigil, Julia needs dialysis because none of the treatments are working. House notices the lilacs in the room that Damien brought her from his garden. House recalls that his mother grew lilacs but there were too many bees around them. A bee sting could trigger Henoch-Schonlein Purpura, a systemic vasculitis. Thirteen says that they could not find the symptomatic rash of HSP. Julia confirms to House that a bee stung her. He searches for the rash and finds it on the roof of her mouth. Julia will recover with treatment.
Sam apologizes to Wilson and they make up. House comes home to find Wilson and Sam back together.
Taub helps Maya with a box at her car. He kisses her. She asks if he wants to go somewhere together. Taub nods.