On the final day of the year-end party, all participants lose all restraint! Men and women, singles and marrieds alike—everyone abandons their inhibitions for a night of wild indulgence. Inviting those who've been important throughout the year, the group rents a private villa with open-air hot springs. Capturing the entire event is renowned director within the group, Koichi Takahashi. His "Side.A" showcases a gathering of diverse attendees, where emotions and desires intertwine. Some join hesitantly, others dive in with full enthusiasm, while a few make no effort to hide their lustful intentions. With unlimited drinks flowing, the night stretches endlessly. How will this party escalate? What will unfold in tonight's final act? An unmissable climax is about to begin!