In thirty minutes, the Bridge at the end of the world will be destroyed. It will go like this: there will be one explosion; then there will be two explosions; then there will be a terrible whistling, a shriek from beyond the stars; and then... silence. And thirty minutes after that the Bridge will fall again. And again. And again. And unless Olala, Damien, and Arum can race up that Bridge and find their way back to a stable present before their thirty minutes are up, this end of the world might claim them, too.