Character Relationship Map: Triangle

Characters

• Momose (played by Sousuke Takaoka) — protagonist
• Kayo (played by Tomoko Tabata) — supporting
• Momo (played by Erena Ono) — supporting

Canonical Relationships

Family, romantic, and professional connections based on plot evidence.

• Momose → Momo (Romantic Unrequited Infatuation) — Momose develops an obsessive, inappropriate attraction to Kayo's sister.
• Kayo → Momo (Family Sisters) — Biological sisters with a protective but strained dynamic.
• Momose → Kayo (Romantic Ex-Partner) — Long-term partners in a stagnant, loveless cohabitation.

Story Analysis

A stagnant relationship is disrupted by the arrival of a younger sister, leading to obsession, conflict, and an unresolved emotional standoff.

Plot Progression

1. Stagnant Union & Arrival — Momose and Kayo navigate a loveless cohabitation until Kayo's younger sister Momo arrives for summer vacation, immediately disrupting the household's equilibrium.
2. Forbidden Attraction & Fracture — Momose becomes infatuated with Momo's provocative innocence, leading to a midnight kiss and Kayo's sharp suspicion. The triangle forces Momose to end his relationship with Kayo.
3. Obsessive Pursuit & Rejection — Driven by fixation, Momose ignores Momo's silence and visits her father's house. He faces physical and verbal rejections from Momo and her boyfriend, while Kayo attempts to maintain contact.
4. Confrontation & Ambiguity — Momose tries to reconcile with Kayo amid escalating tension and a second warning from the boyfriend. The film concludes with an unresolved standoff as Momose watches the sisters.