Tom Butler

Dr. Wells' former protegee -- who can manipulate sound waves -- returns to seek revenge; Iris starts a new job; Joe asks Eddie for a favor -- and asks him to keep it a secret.

In an attempt to recall his plan to defeat the Observers, Walter takes an LSD trip down memory lane in search of answers. Meanwhile, Peter and Olivia trace a mysterious signal into the woods, where they come upon a grisly scene.

Kevin Grady (JONATHAN BENNETT - "Mean Girls," "All My Children") possesses the ability to make people lose their memories. Kevin unleashes his power on Clark, causing him to suffer total amnesia. Chloe discovers Clark's malady and teaches him about his superpowers--while simultaneously trying to keep Clark from accidentally revealing his powers to others. Consequently, Clark meets Lana, becomes enamored of her and decides to share his secret with her. Seizing the perfect opportunity, Lex tries to convince Clark to show him where the three stones are hidden.