Takami has always desired his beautiful elder sister, Hitomi, but has kept his forbidden desires hidden since their parents’ untimely demise. His life takes a dramatic turn when a mysterious girl named Mina appears in his room, revealing herself as Death. Mina declares that it’s time for Takami’s soul to depart, but Hitomi intervenes, pleading for his life. Touched by her sincerity, Mina grants them a deal – if Takami can father a child within a week, he will be granted an additional ten years to live. Left with no other options, Takami now faces a difficult decision: should he succumb to his desires and pursue a forbidden union with his beloved sister?