The galaxy is littered with rogue planets, worlds flung out of the systems that built them, drifting between the stars with no sun to call their own. But when a planet is torn away, does anything go with it? New simulations say yes, a passing star can rip a world out of its orbit and leave its moons still faithfully circling it, sailing off into the dark as a set. If our own Jupiter were evicted tomorrow, all four Galilean moons would go with it. And in that darkness, with no sunlight at all, one of those moons might still be warm enough for an ocean.