In Philadelphia, a troubled and resilient 14-year-old orphan named Billy Batson is in constant search of his biological mother after being separated from her at a young age. Having run away from multiple foster homes, Billy is placed in a new group home where he meets a diverse family of foster siblings, including the enthusiastic superhero fan Freddy Freeman. Meanwhile, an embittered and ambitious scientist, Dr. Thaddeus Sivana, who as a child was deemed unworthy by a powerful wizard, is on a quest to obtain the magical powers he believes should have been his. Driven by a desire for revenge against the wizard and those he deems responsible for his rejection, Dr. Sivana finds a way to harness the powers of the Seven Deadly Sins, demonic entities imprisoned by the wizard long ago.

The same fading wizard, who is the last of his kind, has been searching for a new champion who is pure of heart to bestow his magic upon before he dies and the powers are lost forever. When Billy Batson displays a selfless act of courage, the wizard deems him worthy and Billy is summoned to the wizard's realm. By uttering the wizard's name, "Shazam," Billy is transformed into an adult superhero with a range of powers including super strength, speed, and the ability to wield lightning. As Billy and Freddy explore and test these newfound abilities, Dr. Sivana’s relentless pursuit of power brings him into a collision course with the inexperienced hero, forcing Billy to quickly master his powers or face the dire consequences of their misuse.