House's ex-girlfriend Stacy Warner (guest star Sela Ward) returns - not to be with House, but to get his help for her ailing husband. While House decides whether or not to take the case, Cuddy instructs him to substitute for a sick professor and present a lecture to a class of medical students. As he weaves the stories of three patients (including guest star Carmen Electra) who all present with a similar symptom, House gives a lecture the students will never forget. In the end, they come out with a broader understanding of diagnostics and House's team comes out with a greater understanding of him.