Clark returns to Smallville after his self-imposed exile in Metropolis to face his problems. His and Lana's relationship ends faster than it begins. He meets Perry White, learns more about his biological father, and gains a new ability (super hearing). Finally, sacrificing himself to save his father, Clark agrees to fulfill the destiny that Jor-El wants; pulled into the Kawatche Cave wall, he is transported into space.
Lionel conspires with his old friend Morgan Edge, who arranged for Clark's vial of blood to be stolen. He retrieves the sample and uses the vial in an attempt to cure his terminal liver disease, testing the treatment on a new subject, Adam Knight. However, Lex is brought back home where he undergoes several psychiatric evaluations. When Chloe and Lex learn that Lionel killed his parents, Lionel conspires to make it look like Lex has a psychotic break and institutionalizes him, where he gives him a treatment to make him forget Lionel's misdoings. In attempt to get rid of witnesses for his impending trial, Lionel plans attempts on Chloe and Lex's life.
Season Three takes place during Clark and his classmates' junior year at Smallville High School.
