Nanana's Buried Treasure

龍ヶ嬢七々々の埋蔵金

Nanana Ryuugajou was murdered in her own apartment ten years ago, and her ghost still occupies the cheapest room on Nanaejima, an artificial island reserved for students. Juugo Yama, disowned by his father, moves into that room and takes on her problem: her killer has to be found before she can rest. The trail runs through the Nanana Collection, a hoard of strangely powerful treasures she hid across the island while she was alive, so Juugo joins the school's adventure club and starts digging, with rival hunters chasing the same prizes.