Hikaru ga Shinda Natsu  

The Summer Hikaru Died, 光が死んだ夏, Hikanatsu, Lato, kiedy umarł Hikaru, O Verão em que Hikaru Morreu, صيف وفاة هيكارو, 光死去的夏天

Two lifelong friends, Yoshiki and Hikaru, have always been inseparable. Growing up in a small village with no other children their age, they found comfort in each other's company. Although their friendship appears idyllic at first glance, Yoshiki has noticed a change in Hikaru's behavior since a particular summer. Despite their physical appearance and memories remaining unchanged, Yoshiki senses that something is off about his friend. When he brings this up, Hikaru transforms into an otherworldly being and threatens to kill him if he cannot accept it while also expressing his love for him. Overwhelmed with grief, Yoshiki struggles to come to terms with his friend's transformation and move on with his life. Meanwhile, strange events begin to occur in their village, causing unease and chaos.