When a top secret letter appears outside his bedroom window, Justin suspects it’s a prank. After all, it is asking him to accept an impossible mission, one that everyone has failed at so far. Even a superhero would think twice before accepting this one. And Justin Grey isn’t a superhero… Not even close. In fact, he barely manages to get out of the gym storage closet in one piece after the school bully locks him in. Yet now Justin only has a few days to stop a dangerous gas mix threatening mankind, by following clues around the world and reaching the President of the United States in time.

Joined in his quest by three unlikely friends, Justin is soon being chased around the world by a menacing cloaked man, hell-bent on stopping him. He saves a scientist when he falls into an ice crevasse in Antarctica and scuba dives in the Great Barrier Reef to evade capture with the help of a Spider-Man toy dart gun. The group becomes known as The Earthkeepers and gains notoriety when a video of them goes viral. But there is little time to gloat, as Justin and his friends are too busy getting shot at by bandits on Lake Chad in Africa, managing to flee only after distracting them with a Batman batarang.

It's Justin’s courage that helps him accomplish the extraordinary when he finally ends up face-to-face with the President at the White House after all the evidence the group has collected is stolen.