Kou Ichinomiya (Riku) falls into the Arakawa River and is saved by Nino, a mysterious girl living under the bridge. This encounter marks the beginning of Riku's life change.
Riku, to repay his debt and honor his promise to Nino, decides to live under the Arakawa Bridge with the eccentric community of outcasts and oddballs.
Riku slowly adapts to the unique lifestyle of the community members, engaging in their quirky daily activities and rituals.
Nino reveals she is from Venus, explaining her strange behavior and mysterious aura.
The self-proclaimed village mayor tests Riku's loyalty and ability to live in the community, pushing him to embrace his new life.
Riku admits his growing affection for Nino, which deepens their relationship and integrates him further into the community.
The group faces a challenge from the outside world threatening their peaceful coexistence under the bridge.
After overcoming obstacles and growing bonds, Riku chooses to fully commit to life under the Arakawa Bridge.
