When Supergirl, Surprise Girl, Batgirl, Bumblebee and Katana out of the blue understand they can not bear in mind a single second from their Monday at Tremendous Hero Excessive, the younger DC Tremendous Heroes spring into sleuthing motion! Suspecting foul-play, they band collectively to retrace their steps and uncover the thriller of who precisely stole their recollections – and what nefarious plan is perhaps afoot?