In the middle of a meeting, a woman named Lou is tending to her boss when she swats at what she thinks is an ant crawling on her arm. She then feels another ant on her neck. Lou rips her shirt open, and starts clawing at her bare chest in an absolute panic as she thinks hundreds of ants cover her.
At the hospital, House hides out in a comatose patient's room playing a video game that he stole from the pediatric ward. Cuddy lets him know that Wilson is back to work. House tries to justify why he has not been in contact with Wilson. Foreman comes in to brief them about Lou's symptoms. She suffers from anemia, bradycardia and abdominal pain. House's interest is piqued.
With Foreman, Thirteen, Taub, and Kutner present, House writes on the white board: Hallucinations, possible memory loss, anemia, slow heart rate. The patient also traveled all around the world. Thirteen says that without fever, it's not a tropical disease. Taub suggests that severe B12 deficiency could cause all her symptoms. Thirteen asks why everyone is leaping to conclude a strong career woman has been made sick by her career. She argues that an insulinoma in the woman's pancreas is making her hypoglycemic. House says if they find hypersegmented polys then Taub is right.
Lou is pulling on street clothes in her room while talking on her Blackberry. She protests to Thirteen that her boss has a big Beijing trip planned, but Thirteen urges her to get back into bed. Thirteen administers a shot, and Lou suddenly feels a bowel movement. Her bed is drenched in blood from a rectal bleed.
House finds Wilson writing his resignation letter. He wants to leave because everything reminds him of Amber. "You of all people should know, this is bereavement 101," House chides. "You're saying my pain's a cliche?" Wilson asks. House says that pain fades.
As Taub and Thirteen perform a colonoscopy on Lou, they realize that the patient's heart rate is slow when the bleed should have made it faster. Kutner tells the team that the patient is pregnant. Kutner and Thirteen prepare her for an ultrasound. Lou is surprised by the news, and the ultrasound shows no trace of a baby. House asks the team what could cause bradycardia, a lower G.I. bleed, and two false positive pregnancy tests. Thirteen thinks Choriocarcinoma would trigger pregnancy hormones. Kutner suggests Immunoglobulin. In the middle of the diagnostic, House suddenly gets up and walks out the door.
House goes to Wilson's office and tells him that he is being an idiot. He cannot hide from misery. To House and Wilson's annoyance, the team enters to continue the diagnostics. House tells them the patient tested positive for pregnancy because the patient is pregnant.
House administers an ultrasound to Lou, who says that she is 37. This surprises him because she looks much younger. House shows the patient the monitor where a small, indistinct mass is in her abdomen. He explains that the fetus is using her intestine as a blood supply. He orders Thirteen to "yank the fetus" and put Lou on atropine to raise her heart rate. Thirteen is shocked and questions whether he considered that the patient would want to keep her baby. "People die -- you, Amber, everyone," he snaps, and offers her to quit if she doesn't like his diagnosis. Yet Lou complies, because she has no boyfriend and is on the road with her boss all the time.
House visits Cameron in the ER to discuss Wilson. "Grief means different things to different people," she says, noting that it means very little to him. House asks about what she did when her husband died. Cameron says she moved and got a new job. Cuddy tells House to apologize to Wilson.
Chase operates on Lou, and blood starts filling her abdomen. Thirteen thinks it is a neurological problem. Suddenly, Lou's heart monitor starts beeping with cardiac arrest.
With House's phone vibrating, he ignores it to plead with Wilson to stay. His friendship matters more than this patient. Wilson can't believe this. Foreman is desperately administering CPR and pumping Lou's chest as House leaves without looking back.
The team asks Cuddy what they should do without House. She wants them to continue doing their jobs. Thirteen diagnoses Multiple Sclerosis. "If a lesion took out the sympathetic innervation of her heart it'd explain the bradycardia and the blinking," she says. Although this does not cover the vitamin deficiency or the ectopic pregnancy, Foreman agrees to start Lou on interferon to treat M.S.
Cuddy goes to House's apartment to scold him. She had warned him not to take the case and instead deal with Wilson. House slams the door on her. "You're doing the same thing he is," she exclaims. "You're running away."
Lou develops a fever, which means the team was wrong about M.S.
House comes back to the hospital because Cuddy had his home cable disconnected. Wilson enters, responding to Cuddy's emergency page. She threatens to withhold Wilson's salary history from all hospitals in the Tri-State area and to permanently set every TV in the building to the Pottery Channel unless they both sit down and talk.
The team reviews a video of the surgery. Kutner notices something as the bowel is being reconnected on the tape. He thinks it looks like a ganglioma. Foreman agrees that this could be causing all of the patient's symptoms. They need to open her up to get a piece of it. Foreman, Thirteen, and Kutner consult Chase, but he refuses to operate on Lou again. Kutner suggests they insert a lighted scope through her rectum. This will move the intestine to find the ganglioma then push it to the surface.
Lou admits to Thirteen that she has been replaced at work. Although Thirteen is angry, Lou seems fine with it. This angers Thirteen more.
Cameron goes to Wilson to prevent him from leaving and they discuss the pain of grief.
Examining Lou's intestine on a video microscope, the team throws out possibilities. Thirteen thinks it is abnormally deposited proteins, which means lymphoma or amyloidosis. Foreman concurs with Wilson's diagnosis -- it is lymphoma.
Lou is hooked up to chemotherapy. She's tired, but more alert than she's been. Thirteen informs the patient that she has Huntington's Chorea. Lou admits that Thirteen's reaction to her firing has convinced her to apply for new jobs.
House returns to the hospital and checks in on Lou. He asks if she has any bruising and she points to a bandaged area. House jams a large needle into one of her bruised areas as she screams in pain. House says Lou has diffuse lepromatous leprosy, which is also known as "pretty" leprosy because it makes your skin appear younger and smoother. Her bruises are really mycobacterial lesions. Physical stress from a pregnancy triggered e-nodosum leprosum, a common complication of leprosy. This inflamed Lou's nervous system, including the nerves to her heart, which made it hard for her body to absorb vitamins. This explained her B-12 problem. It also scarred her Fallopian tubes, so her fetus fell into her abdomen.
Thirteen is doing paperwork as House enters. "Almost dying changes nothing," he says. "Dying changes everything."
Wilson is packing his office, and House comes by to finally apologize for his role in Amber's death. Wilson doesn't blame him, but says he is the real reason that he is leaving the hospital. He just needs to get away from House. Wilson leaves with his packed box.