Growing up in post-World War II era Arizona, young Sammy Fabelman aspires to become a filmmaker as he reaches adolescence, but soon discovers a shattering family secret and explores how the power of films can help him see the truth.

After years of being sheltered from the human world, the Turtle brothers set out to win the hearts of New Yorkers and be accepted as normal teenagers through heroic acts. Their new friend April O'Neil helps them take on a mysterious crime syndicate, but they soon get in over their heads when an army of mutants is unleashed upon them.

When their trip to San Lorenzo takes a turn for the worst, Arnold and his classmate’s only hope of getting home is retracing the dangerous path that led to Arnold's parents' disappearance.

A heroic group of teens sheltered from the dangers of the post-apocalyptic world receive a message that inspires them to leave the safety of the only home they have ever known and embark on a cross-country journey to find the one man who can possibly save the world.