After a car accident kills their parents, twins Haruka and Sora Kasugano return to their grandparents' countryside home in Okukozome. Haruka reconnects with childhood friend Nao Yorihime and neighbors Kazuha and Akira Amatsume, while Sora—withdrawn, internet-dependent, and unwilling to leave the house—clings to her brother as her only anchor. The series follows an omnibus format, branching into separate romantic arcs from a shared starting point.