The Summer Hikaru Died novel volume 1 was adapted by Mio Nukaga and is based on the work, and features illustrations, by Mokumokuren.

The bond between Yoshiki and Hikaru is a welcome escape from their isolated village. But one fateful day when the two boys meet up, Yoshiki can immediately tell something is off. Though the person standing before him wears Hikaru's face, Yoshiki knows that his friend is…gone. It is then that Yoshiki makes a decision. Although things will never be as they once were, he would prefer this Hikaru to no Hikaru at all.