After facing humiliation at a high school reunion, the Matsuno sextuplets, feeling inadequate as NEETs compared to their accomplished peers, drown their sorrows in alcohol. Their night takes a surreal turn when they wake up in a memory realm focused on a major regret from their school days. Confronted by their past selves and friends' embarrassing moments, the sextuplets must discern whose remorse binds them in this realm to escape back to reality. Racing against time as the memory world crumbles, they strive to correct the past before it's too late.