As Denise and her mother make their way to the temporary shelter they've been assigned to in response to the comet that is about to hit Earth, they can't find her sister Iris anywhere, and their mother's drug addiction is slowing them down. Denise fears they'll never reach the shelter in time. And when they come upon a ship scheduled to leave Earth to repopulate other planets, Denise worries they won't be allowed on board because of her mother's drug problem and her own battle with autism.