An experiment at the Luthor fertilizer plant makes an old friend of the Kents literally shake and jitter, and he seeks vengeance against the Luthors, who hide the secret of his transformation behind "Level Three" at the local plant.
A man from Lex's past stalks him in conjunction with a mysterious death at Club Zero that Lex may have been responsible for. Meanwhile Chloe looks into Clark's past as an adopted child.