Umbra and Antumbra are twins. Just by touch, Umbra has the ability to steal good luck from people, while Antumbra has the ability to give bad luck. As long as they're together, their abilities cancel each other out, so neither girl knew about her power until the twins split up to go to different universities. Things started getting ridiculously easy for Umbra, while Antumbra lived the life of an outcast as misfortune befell the people around her. Antumbra can only live a normal life if she's near her sister, but Umbra has been using her power to gain fame and fortune and wants nothing to do with her twin. In fact, Umbra wants Antumbra dead! With the help of a mysterious stranger, Antumbra fights to regain her sister's love and fix the balance of luck in the universe.