I’d always known Calam would run. He had all the signs. A taut restlessness, body brittle as an overstretched lute string, when we stayed too long in one place. A gloom in his eyes, as we drifted through stretches of dead space. A sullen crease between the brows, whenever I tried to ask how he’d landed in that dead-end Martian workshop at seventeen. But after ten years, why now?