A kid watches his best friend die, goes back in time to save her, and discovers the real horror isn't what killed her, it's that he keeps running out of time. The first half builds mystery with actual teeth, each loop pulling back a different layer of what's wrong with this island. The second half abandons that tension entirely and opts for spectacle, but the damage is already done: you're too invested in these people to stop watching even when the writing betrays them.

Shinpei Ajiro comes back to his home island of Hitogashima for the first time in two years to attend the funeral of his childhood friend Ushio Kofune, who drowned while trying to save a little girl. What should be a somber reunion quickly turns darker. His best friend Sou tells him about bruises found on Ushio's neck, raising the possibility of murder, and the next day the family living next door vanishes. Ushio's sister Mio recalls an old island legend about Shadows, beings said to foretell the death of anyone who meets their own. As strange events pile up, Shinpei sets out to uncover the truth and honor Ushio's last wish, to keep Mio safe. The result is a supernatural mystery thriller that casts a small summer island in an ominous light.