31-40. (same as episodes 1-10, and 13-16)
: Ben frees Ghostfreak from Vilgax's prison to save Vilgaxia. Trade-Off! : Kevin and Darkstar team up to regain their human forms. all ben 10 alien force episodes
Ben puts the Omnitrix back on, which reconfigures into a new set of aliens. Kevin's Big Score Kevin proves his loyalty after a rocky start with the team. What Are Little Girls Made Of? Introduces Ben and Gwen's Anodite grandmother, Verdona. 31-40. (same as episodes 1-10