Billions of years ago, a being known as The Wizard found a way to harness the power of the Egyptian Gods, and swore an oath to use that power only for good. When he became too old to defend the Earth himself anymore, he started granting mystical powers to mortals pure enough to use them for good. One such mortal, known as Black Adam, went mad with the powers granted to him by The Wizard, and The Wizard himself had to defeat Black Adam, exiling him to another realm. In the present day, Black Adam escapes from his prison and attacks The Wizard, nearly killing him. The Wizard is able to escape out into the mortal world, and sets out to find someone worthy of his power, so that they may defeat Black Adam.
Billy Batson, a rebellious orphan boy living in Fawcett City, is chosen after saving the disguised Wizard from getting hit by a car. Billy is given mystical abilties, and is told that when he yells out "Shazam" he will transfom into a godly form. At his foster home Billy says Shazam and is transported to The Wizard's realm, where he first transforms into his powered form and trains, learning of Black Adam and how he must stop him. Billy, not wishing to carry this burden, returns home and refuses to use his powers.
Meanwhile, scientist Thaddeus Sivana is investigating weather patterns, and theorizes that an extradimensional being has been using a wormhole to transport back and forth between dimensions. Sivana's daughter, Beautia Sivana, believes her father to be crazy, and his obsession with his research pushes them even further apart. After being mocked and humiliated by Beautia's fiancee / Billy Batson's foster father, Dudley H. Dudley, Sivana attempts to kill him by programming a military-grade battle android to attack him at his and Beautia's wedding. Billy transforms into Shazam and saves Dudley and the party guests, including his foster sister Mary Bromfield. Later, Billy, noticing a Sivana Labs logo on the android, arrives at Sivana's laboratory to confront him. Sivana believes Shazam to be one of the extradimensional beings, and attacks him. Shazam defeats him easily, and learns that, based on Sivana's research, there is another extradimensional being on Earth.
Back in The Wizard's realm, Billy learns that Black Adam was an Egyptian slave who stood up to a cruel pharoah, and thus The Wizard chose to grant him mystical powers in order to fight the forces of evil. Black Adam, still vengeful against society, went on a rampage, and The Wizard had no choice but to send him to another dimension. Black Adam, who has recently returned to the mortal realm, attacks the White House, seeing the American government as the new tyrannical force opressing society. Realizing her father was right, Beautia Sivana calls off her marriage to Dudley and goes to her father's laboratory to reads his research, finding designs for a special wormhole generator to send these extradimensional beings into an inescapable void. Shazam appears and tells Beautia that he wishes to stop Black Adam, so he agrees to free her father from prison to help build the wormhole generator.
Shazam brings the Sivanas to Washington, DC, and retrieves for them the materials needed to build the generator, going so far as to steal plutonium for them. Shazam quickly arrives at the White House, and fights against Black Adam, who is even stronger than he antiipated. After the Sivanas finish constructing their device, Shazam lures Black Adam out into the open, and they activate the generator, opening a large vortex that sucks in both Shazam and Black Adam. The two find themselves flying through a dark void, with no way out. Shazam and Black Adam continue to fight, and eventually Shazam loses consciousness, turning back into Billy Batson. Black Adam tries to kill him for ruining his plan, but Billy is saved by The Wizard, who brings him back to Fawcett City. The Wizard, having used the last of his magic to go into the void, dies. Later, Billy returns home, and reveals to Mary that he is Shazam, the hero who defeated Black Adam.
In a mid-credits scene, Black Adam is floating alone, through the void, when he hears a voice calling to him. He drifts further into the darkness and comes face to face with a giant caterpillar.
- Finn Wolfhard - Billy Batson
- John Cena - Shazam
- Rowan Blanchard - Mary Bromfield
- John C. Reilly - Dudley H. Dudley
- Michael Gambon - The Wizard
- Dwayne Johnson - Black Adam
- Robert Englund - Dr. Thaddeus Sivana
- Brie Larson - Beautia Sivana
- Peter Cullen - Mr. Mind