Kivi wasn't allowed in the engine room. No one was. But she couldn't resist. She just had to see the mechanical wonder that powered the colony ship that was her whole world. So she snuck inside to catch a glimpse of the heart of the Lucy... just in time to witness it lurch to a stop.

When she emerged from the engine room, the ship that had once been bursting with people was dark and empty. She could only find one other person, an older boy named Tron, who'd been kept in isolation for years; a boy the adults decided was too dangerous to live with everyone else.

But there is no time to hold grudges, or to figure out what happened to their missing family. The engine is dead. Without that there is no light, no gravity, no heat, no air... They have to work together to figure out how to operate the ship and survive, or the Lucy will be one more dead ship drifting through the black.