In a mansion high above the city, the life of Shindo Kei, the last remaining heiress of the Shindo family, hangs in the balance. Centuries ago, a Grim Reaper placed a curse on the Shindo family: none of its heirs would live beyond their twentieth birthday. With Kei's final birthday just hours away, Kawahira Keita and his plucky Inukami partner, Yoko, have challenged the Grim Reaper to a duel. If Keita wins, the Shindo curse will be broken forever, Kei's life will be saved, and Keita and Yoko's financial troubles will be a thing of the past. But the Grim Reaper isn't known for playing fair, and has some dirty tricks up his tattered sleeve.