Same to Ikiru Nanokakan

One night, Fukami Kyouhei wakes up on an unfamiliar beach. All he sees is the vast ocean and sand... until he feels something odd on his head. To his horror, a naked girl with a shark-like appearance is biting him! He flees, only to encounter a girl in a swimsuit who joyfully hugs him, claiming to be his childhood friend. Then, the shark girl catches up and accuses him: 'Kuu. This person assaulted me.' The air freezes. His 'childhood friend' gives him a cold stare as the shark girl repeats the accusation. Sirens blare, handcuffs lock—Kyouhei's in crisis just minutes after waking! Meet the sporty childhood friend Remi, the high-handed gourmet Amane, and the cute shark-like Kuko. On this island of mysteries, Kyouhei's fate tangles with these girls in a thrilling loop of time and memory.