When the boy hero Shazam is offered to join the Justice League he is reluctant about it, but when his rivals the Monster Society put the League in peril he's the only one who can save them.

10-year-old Billy Batson shouts a single word and, with lightning bolts flashing, he transforms into Shazam!, a full-fledged adult Super Hero. It doesn't take long for Superman, Wonder Woman, Batman and the rest of the Justice League to take notice and invite the earnest do-gooder to join the team. But to become a member, Billy must reveal his true identity. While fighting off the evil Mr. Mind and Black Adam, Billy learns that he must trust others - and that nothing creates trust like helping those in need.