Nanatsu no Hikan

One day, a young man from a high-classed background named Ippei is called to the office of his uncle, Shujiro. Shujiro is the current head of his family who is concerned about seven mansions left behind by the last clan head (Ippei's grandfather, Shuhei). The seven mansions were strangely built in a Big Dipper formation on a remote island and have never been fully explored by the family members of...