We are introduced to Mr. Foster after his son is admitted to hospital. He is upset that Keith's girlfriend Pam crashed his Porsche, but not because of the value of the car - it was a gift from his late wife. He does not like Pam because she was in rehab at the age of 11 and he believes she is a bad influence on his son.
As the team has trouble diagnosing Keith, it soon appears that he will need a liver transplant. However, just before the transplant, House learns that the family cat Jules has recently died. He has his team dig it up so he can do an autopsy on it. He learns the cat died from napthalene poisoning and figures Keith has the same thing. He also realizes that if Keith gets the liver transplant, the replacement liver will fail as well.
In order to stop the transplant, House breaks into the operating room and deliberately breaks the sterile field. They have to cancel the operation. When Mr. Foster learns of this, he hits House. However, after House explains the diagnosis, Foster calms down and lets House proceed.