My son's first friend, Shunya, came over to our house. He's a top student, trusted by teachers, and a central figure in his class. As a mother, Sereino welcomes Shunya with joy, seeing him as her son's friend—but his true intentions lie elsewhere. Having long been attracted to Sereino, Shunya uses his friendship with her son to gradually win her affection, eventually making his move. Drawn in by his charm, Sereino finds herself unconsciously consumed by Shunya's desires. At the intersection of warmth and tension, their relationship slowly deepens.