A Luthorcorp experiment is released into the atmosphere - a toxin that causes its victims to hallucinate their worst fear. Chloe, Clark, Lana, and Jason all fall fictim to the toxin, and Lex, desperate to find a cure, takes a dangerous antidote. Meanwhile, Lionel is released from prison and his conviction overturned thanks to a mysterious benefactor.
Elenco: Tom Welling , Erica Durance , Allison Mack , Aaron Ashmore , Annette O'Toole , Callum Blue , Cassidy Freeman , Eric Johnson , James Marsters , Jensen Ackles , John Glover , John Schneider , Justin Hartley , Kristin Kreuk , Laura Vandervoort , Michael Rosenbaum , Sam Witwer , Samuel L. Jones .