For physicist Armin Richter and historian Sam Osei, love has always been an equation of time and space. When Armin is chosen for the most ambitious mission in human history—a one-way journey to colonize a planet twelve light-years away—they refuse to accept a lifetime of separation. They craft The Plan, a brilliant, audacious, and near-impossible strategy to reunite. While Armin endures the cold sleep of hibernation and the brutal realities of interstellar travel, Sam will dedicate his life on Earth to securing a spot on the second ship, launching seventeen years later. It is a promise made across a relativistic gulf, a testament to a love that believes it can conquer the laws of physics.

But the universe does not care for human promises.

For Armin, the journey through the void is a slow erasure of the self. Each four-year hibernation cycle costs him a piece of his humanity, stripping away the man Sam loved and replacing him with a cold, pragmatic survivor forged in silence and isolation. When his ship, the Genesis, finally arrives at the new world, it is not the empty paradise they were promised. It is a planet that has been waiting, home to a hostile alien lifeform that threatens to unravel not just the mission, but the very matter of their existence. Faced with an impossible choice, Armin must decide the fate of his crew and this new world, a decision that will harden him in ways Sam cannot imagine.

For Sam, left behind on a perfect Earth, the seventeen years of waiting are a different kind of war. It is a battle against the crushing weight of silence, against the ghost of a man who grows more distant with every data-burst from the void. As he dedicates himself to The Plan, navigating the cutthroat world of academia to earn his place on the second ship, he discovers that a life lived in waiting is not a life at all. The years change him, the loneliness carves new lines on his soul, and the promise he made as a young man feels like a chain, shackling him to a past that is fading with every light-year his husband travels.

When Sam finally arrives on the new world, he is not the man who said goodbye, and the hero who greets him is not the man he remembers. They are strangers who share a history, two survivors of a beautiful, failed experiment. The Plan has succeeded, but the men it was designed for are gone. Can they build something new from the wreckage of the past, on a hostile world that may not want them there at all? Or will they discover that the distance between two hearts is the one void no ship can ever cross?