Two girls appear in a world where morning and evening exist simultaneously, separated by an invisible boundary. Asa moves through the sunlit side while Yuu inhabits the twilight realm, and they've never met despite living in the same place. When their paths converge through an unexpected accident, they discover they can share a single moment where both times occupy the same space. The encounter awakens something in each of them: a longing to understand what exists beyond their familiar half-day. They begin leaving messages across the boundary, learning that their worlds are more connected than they believed. As the song plays, their friendship blooms in stolen moments between sunrise and sunset, defying the natural laws that kept them apart. This is gentle, whimsical storytelling set to music. The animation captures a dreamlike quality where impossible things feel inevitable. What emerges is a quiet meditation on connection across difference, framed through the eyes of two girls discovering that the world is larger and stranger than they imagined.