On her eighteenth birthday, shut-in Sena Shirai finally works up the courage to leave the comfort of her home—only to be hit by a truck! Luckily, she has a second chance at life as a witch in another world, but the only spells she can use are "explode" and "perish." Unable to control her destructive power, Sena is shunned by the nearby villagers and doomed to live in isolation once again. But when a mysterious boy collapses at her doorstep on her (second) eighteenth birthday, will her fate finally turn around?