"Chuck Versus the Lethal Weapon" is the sixteenth episode of the second season of Chuck. It originally aired on March 9, 2009. When Cole Barker (Jonathan Cake) escapes after being tortured by Fulcrum and returns to Castle, Sarah Walker and John Casey are assigned to hunt down a scientist (Robert Picardo) codenamed "Perseus", who is the mastermind behind Fulcrum's plans to build their own Intersect.