17-year-old Monica is left to take care of her exuberant younger sister for the week. Their emotionally unavailable mom, who Monica aimlessly depends on, is away at a "business conference" (really chasing after, yet another, man). As the girls rush to school one morning, the tornado sirens suddenly wail outside. They spend 15 minutes trapped together in a storm-shelter closet. Face to face with disaster, Monica must rise to the occasion and be the mom that she herself has never had.