Onda Miku was just an ordinary high school girl who loved nails. But suddenly, she was involved in a terrible accident, and the shinigami (death god) Sei fastened Thanato's Lover, his chain of death, onto her wrist! However, she was taken by mistake and brought back to life, yet the chain cannot be removed until the end of her lifespan. She is now chained to Sei until then. Sei may be hot, but he is a bit scary. Being tied together with him, just what kind of fate awaits Miku!?