In 1939, Captain Daniel McCormick, Mel Gibson, is a United States Army Air Corps test pilot who achieves a remarkable test flight and, after a crash landing in a prototype North American B-25 Mitchell bomber at Alexander Field in Northern California, is greeted by his longtime friend, Harry Finley, George Wendt. Finley shares a groundbreaking secret: his latest experiment, "Project B," has succeeded in building a prototype chamber for cryogenic freezing. The next day, just as McCormick is about to propose to his girlfriend, Helen, Isabel Glasser, she slips into a coma following a car accident, and doctors doubt she will recover. Stricken with heartbreak, he asks to be placed in suspended animation for a year so he won’t have to watch her die.
Fifty-three years later, in 1992, Nat Cooper, Elijah Wood, a ten-year-old airplane enthusiast, and his friend Felix explore a military storage warehouse that houses the cryogenic chamber. A reckless moment leads to the chamber starting up and McCormick waking to a world that has moved on, leaving Nat’s coat behind. He escapes before realizing what year it is and initially turns to the military, only to be dismissed as delusional. Determined to uncover what happened, he follows the jacket’s address back to Nat and forms an unlikely bond with the boy.
While hiding in Nat’s treehouse, McCormick saves Nat’s mother Claire Cooper, Jamie Lee Curtis, from her abusive ex-boyfriend Fred, Eric Pierpoint, injuring his hand in the process. Claire nurses him back to health, and a quiet, growing bond develops between them. She offers him shelter, and the duo, along with Nat, constructs a mock bomber cockpit in the treehouse so McCormick can teach Nat how to fly. But his renewed life comes with a harsh cost: his body begins to fail as time catches up, and a hospital visit reveals the aging process is accelerating uncontrollably.
McCormick seeks out Susan Finley, Millie Slavin, Harry Finley’s daughter, who explains that her father died in a laboratory fire before she was born. The FBI later uncovers a warehouse lab blaze in the early 1940s, and it’s revealed that the scientists, including Finley, died trying to rescue the frozen McCormick. The public never realized there was a cryonics chamber, misidentifying it as a water heater, which led to McCormick’s accidental 53-year slumber. Susan presents him with her father’s journals, detailing the cryogenic process, and reveals that the aging is irreversible. She also shares that Helen remains alive, and the trio must keep ahead of the FBI, who are closing in.
The story shifts toward a daring rescue mission as Claire drives McCormick toward an air show and commandeers a B-25 bomber to reach Helen’s seaside lighthouse home, with Nat stowing away on board. Claire passes Harry’s journals to the FBI to aid attempts to replicate and modernize the experiment, hoping to preserve the possibility of a cure for others. As aging accelerates once more, Nat lands the plane in a field near Helen’s house, and the once-vibrant McCormick reunites with the now gray and wrinkled Helen. He asks her to marry him, and she joyfully accepts, proving that true love can endure through time. The film closes on a hopeful note as McCormick introduces Nat to Helen, and the three join hands for a quiet seaside stroll, symbolizing a future where love, memory, and second chances endure.
