After the sudden disappearance of Gabe (Rufus Sewell), a physicist, during a business trip, his young son Erol (Haley Joel Osment), wife Marika (Gillian Anderson), and father Sal (Victor Garber) are left devastated and struggling to cope. Even after years have passed, they remain haunted by Gabe's inexplicable vanishing act.
But when Erol grows up to become a brilliant young scientist himself, he stumbles upon a discovery that may hold the key to bringing his father back. Erol realizes that his father may have actually traveled through time and space, leaving behind a trail of scientific clues that Erol is determined to follow.
With the help of his grandfather Sal, Erol embarks on a dangerous journey that takes him to the very limits of scientific discovery. Along the way, he must grapple with the ethical implications of his research and confront his own personal demons. But as he grows closer and closer to unraveling the mystery of his father's disappearance, he also comes to realize that the answers he seeks may not be what he had hoped for.
As the tension builds towards a startling conclusion, I'll Follow You Down explores the mysteries of time and space, the limits of scientific knowledge, and the bonds of family that cannot be broken, even across the vastness of the universe.