With Christmas approaching, the Musatani Shopping Center finds themselves up against a giant department store that has appeared recently. Suzu, who is asked to help bring younger customers to the shopping center, has Sonico, Fuuri, and various others to act as Santa girls to appeal to customers and increase sales. When the department store responds by employing some popular idols to draw the customers away, Suzu decides they need an official Santa Claus to appear on Christmas Eve to appeal to parents and children. On her way home, Sonico encounters a young girl named Ayaka who upset about her father not being able to come home in time for Christmas. On Christmas Eve, Sonico brings Ayaka to meet Santa, who turns out to be Ayaka's father, bringing her the present she wanted the most.