Nicole Bilderback

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.

When a prominent astrophysicist is found dead in her car, Castle is led to theorize her death was the result of an alien abduction.

The death of a young botanist leads the CBI team into the lucrative world of medical marijuana, while Cho's work with the rapid response team brings him back into contact with his former girlfriend and confidential informant, Summer Edgecombe (returning guest star Samaire Armstrong).

Something's cooking when Aunts Hilda and Zelda use man dough to bake a date for Sabrina.

The team investigates a body found at a glass recycling plant with a diamond lodged in its jaw. French Inspector Rousseau approaches the team with an accusation against the Marquis De Chaussin, who is revealed to be the victim’s husband and lives in Virginia. Meanwhile, Booth discovers he suffers from a temporary eye illness, and Hodgins thinks he’s being followed by a ghost.