In a shocking episode, Dr. Lawrence Kutner, played by actor Kal Penn is dead. Dr. House was curious why he did not show up to work, and sent Foreman and Thirteen (aka Dr. Hadley) to investigate. When they enter his apartment, they find him laying in a pool of blood. Suicide by self inflicted gunshot wound.
House takes this on as his main focal point of trying to solve the mystery of why Kutner would kill himself. There is a couple, an older man and woman. The man, played by Meatloaf, is having heart problems, and the woman fakes illness to be close with her husband.
As the episode unfolds, it turns out that the woman really does have something wrong with her, and She is bent on attempting to save her husband. The plot continues to revolve around the issue of suicide, from the woman trying to kill herself to save her husband and donate her heart, to her husband demanding to donate his kidney to save his wife, and of course, Kutner's suicide, which House simply cannot wrap his mind around.
House continues to focus more on solving the mystery of why Kutner would kill himself than on the mystery of what is wrong with the now mysteriously ill woman. House persuades Cameron to talk to Meatloaf and have him agree to donate his kidney to his dying wife. He will die on the table, but he only has a few days to live. He agrees, but then Cameron tells House that there are nodules on Meatloaf's fingers, and he may have a curable disease.
She's correct, and House tells him that he has a fungal infection and he's completely curable. He tells house that they'll be scraping up his remains to give a kidney to his wife. His plans are foiled when Taub tells the woman that her husband has a curable disease, but he wants to donate his kidney, if that's okay with her.
Meanwhile, House has decided that there is no plausible reason for Kutner to commit suicide, so it must have been murder. Now he is investigating the "murder" of Lawrence Kutner. Wilson is appalled, and tells House that all he cares about is the mystery of it all. He is not there because he cares about Kutner. He only cares to solve the puzzle. He says that's all it is to House, is a mystery to be solved. That's all anything ever is.
The woman is getting worse, and it finally occurs to House that if she is sick, and they can't figure out what is wrong, then all the clues must not be there. Everybody lies, so she lied about something. He bursts in and asks why she would think the beaches of Rio are the same as the beaches of Hawaii. It turns out, she was bitten by some sort of fly. She comes clean and tells her husband that she just got tired of waiting for him to come so they can have their dream vacation in Rio, and she went with someone else.
It's too late, however. She was not diagnosed in time.House continues looking through Kutners apartment, while everyone else attends the funeral. Taub, staying behind at the hospital, finally breaks down and cries.
At the end, Fox asks viewers to go to fox.com/kutner. At the new mockup site, there is a tribute to Dr. Kutner. This makes it seem as if Kal Penn, the actor, is perhaps not living anymore, but at this point I have seen no evidence of such. Please do let me know if this is incorrect.