The Lunch Club is back (in time) in their latest adventure! It's history week at Pleasant Valley Elementary. Mr. Peabody has organized some very cool AND educational events. But Leo and Tia haven't seen him since he vanished into a weird portal, along with the villainous McSticky. When Mr. Peabody suddenly reappears, he comes bearing bad news: McSticky, has a dangerous space-time ray and he's not afraid to use it . . . to change the course of history! Will the Lunch Club gang be able to stop him in time?