The Summer Hikaru Died

In a remote mountain town, Yoshiki notices his childhood friend Hikaru is not the same after vanishing for a week and returning. The person beside him looks and sounds like Hikaru but is an otherworldly being wearing his shape and memories. Yoshiki hides this and keeps meeting him at night, testing what the impostor recalls and what it cannot imitate. Odd events ripple through the area as strangers ask about the mountain and elders hint at a buried Indo family secret. A low key inquiry leads Yoshiki back to the ridge where something opened, while a man named Tanaka appears with knowledge of what nests there. The facade strains as the entity grows attached to Yoshiki yet reacts to threats with inhuman reflexes. Hunters and officials close in, forcing choices between exposure and escape. The story tracks late summer into autumn as the pair probe the mountain’s origin and face whether they can stay together when one of them is no longer human.