サマータイムレンダ

Shinpei Ajiro returns to his hometown on the remote island of Hitogashima in Wakayama Prefecture after learning of the death of his childhood friend, Ushio Kofune. At Ushio’s funeral, he reunites with her sister Mio and other island residents, but strange events begin to unfold, hinting at an unnatural presence. Shinpei discovers the island’s legend of “shadows,” doppelgangers that mimic people and are tied to mysterious deaths. As he investigates Ushio’s death, he encounters unsettling phenomena, including sightings of Ushio’s shadow. The escalating mysteries pull Shinpei into a suspenseful confrontation with the island’s dark secrets, blending time loops and supernatural elements. (Unreviewed summary by Grok 3)