Ryan (from "Stray") returns and Clark has to save him from Dr. Garner of the Summerholt Research Facility. Meanwhile, Aunt Nell leaves Smallville, and Lex wants to expand the plant but runs afoul of the mayor.

Clark and Lana each make an attempt on Chloe's life for unknown reasons after they receive a mysterious e-mail from the Summerholt Institute. Clark must discover the source of these e-mails after Chloe reveals she has uncovered proof that they are doing mind-control research at the lab and realizes they must be trying to kill her in order to prevent her from writing an expose. Meanwhile, Lana decides to rent the apartment above the café to Adam even though she feels he is hiding something dangerous about his past.

Believing that key information about his father's past was lost when his memory was erased, Lex decides to join an experimental program with Dr. Garner to regain the information so he can turn his father over to the FBI. Knowing that Lex will discover his secret if he regains his memory, Clark tries to stop him but is caught by Lionel and the doctor and exposed to the same radical treatment so that Lionel can solve the mystery of Clark's past.