In a series of interviews with the KND after they're all grown up, the former operatives are temporarily brought out of their decommissioned haze to discuss what happened during their very last mission with Numbuh one - where he disappeared and was never heard from again! It all started with a routine mission to get the Delightful Children's birthday cake, but when a mysterious boy steals it instead, he makes it available to whoever wants it, IF they can solve his 'simple' scavenger hunt first. ...