When Keith was hallucinating, he called out Jules' name. This intrigued House who wanted to know who Jules was. Pam told him that it was the family's dead cat. House wondered why he had not been told about a dead cat and the family told him the cat was very old and it was no surprise it died.
Nevertheless, House sent Foreman and Chase to exhume the cat out of frozen ground so he could perform an autopsy on it. He discovered the cat had died from napthalene poisoning. He soon realized that Keith had it too and that if he didn't stop the upcoming liver transplant, the new liver would be damaged as well. He interrupted the surgery by breaking the sterile field and was assaulted by Mr. Foster. However, House turned out to be right and Keith improved with treatment.