Clark and Lana each try to kill Chloe 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 the laboratory is involved in mind-control research--and someone wants to prevent her from writing an exposé. Meanwhile, Lana rents the apartment above The Talon to Adam (recurring guest star Ian Somerhalder), even though she feels he is hiding something dangerous about his past.