The storyline of this OVA serves as a conclusion to the narrative arc established in the 2020 predecessor. It focuses on the psychological deterioration of relationships under external pressure. The plot centers on Yui Tachibana and her boyfriend Kou, whose lives are disrupted by the intervention of an adult figure who exploits their secrets. The "End of Summer" subtitle acts as a thematic metaphor for the transition from youth and innocence to a more somber and permanent reality, illustrating the breakdown of the couple's bond.

The most important line in the film is never spoken aloud. The power is in the glances, the paused sentences, the sudden “Never mind.”

An authority figure who serves as the catalyst for the story's conflict, using manipulation to drive a wedge between the protagonists. Thematic Elements