Ted tries to keep Robin from going on a camping trip so that she can spend time with him. Barney enlists the help of an old flame to perform a rain dance. At the same time Marshall finds out about Lily's interview for the fellowship in San Francisco.

When Stacy insists her husband Mark get tests, House insists he can handle things. But despite the fact Mark's tests prove negative, his steadily growing symptoms indicate he is dying. While House struggles with the mystery and makes increasing demands on his staff, Wilson worries about House's emotional well-being, and Cuddy considers adding a new employee to the clinic.

As the CSI's continue their search for and discover the identity of the "Miniature Killer", Grissom and Sara's relationship gets exposed to the rest of the team as she goes missing during the investigation. The "Miniature Killer" is finally captured, but not before a member of CSI becomes the killer's final victim.

A new military contingent from Earth is sent through the Stargate to take command of Atlantis and defend it from the impending Wraith attack.

Chuck learns the most shocking secret of her life and refuses to forgive Ned. In order to take the Pie Maker's mind off of Chuck, Emerson gets him to solve the mystery of a man killing life insurance agents and hiding them in snow banks. Oscar Vibenius returns to investigate why Chuck has a unique smell. Meanwhile, the Aunts' antidepressant-laced pies begin to show some hallucinogenic effects.

After passing Zara and Ching's tests, Clark learns that they want him to leave the Earth (and Lois) and go back with them to rule New Krypton. If he refuses, the planet will be ruled by the evil Lord Nor, who sends an assassin to kill Clark before that can happen. When Clark defeats the assassin, he and Lois decide that he must go with Zara and Ching. Clark says goodbye to his parents, to Earth and to Lois, and leaves with Zara and Ching.