Tsukushi Makino brings Ryusuke Hayama with her to spend Christmas with Tsukasa Domyoji. Cross, Tsukasa bickers with Ryusuke but acts nice to him at the zoo. While Ryusuke sleeps, Tsukushi asks Tsukasa why he is nice to her.
Ryusuke Hayama happily declares that he wants a chocolate parfait. An irritated Tsukasa Domyoji says something rude to the child and Tsukushi Makino hits him to shut him up. At a restaurant, Tsukushi notices that Tsukasa is still mad. She understands his irritation, though a part of her is relieved not to be alone with him. Ryusuke suddenly ask the two if they are "lovers," earning over-reactions from both. He then says "That means I have a chance." Tsukasa yells "You're just a kid!"
Ryusuke asks Tsukasa "Who are you, anyway?!" He informs him that he is the heir to Domyoji Group and calls Ryusuke's father's company "small potatoes" in comparison. Ryusuke then begins asking him what he has, such as helicopters and villas. Tsukushi stops the fight. Tsukasa softens a bit, when Tsukushi compares Ryusuke's childhood to his own. Afterwards, the three go to the zoo. Tsukasa surprises them by hoisting Ryusuke onto his shoulders in order to give him a better view of the animals.
Later on, Tsukasa is still holding Ryusuke, who has fallen asleep, and reaches to hold Tsukushi's hand. An elderly woman comments "My, what young parents!," causing Tsukushi to instantly pull her hand away. Tsukasa then asks her about her relationship with Seinosuke Amakusa, but she refuses to answer at first. She eventually says "I hurt Kinsan very badly, but he just took it with a smile." Tsukasa does not reply, changing the subject. Tsukushi then asks him "Why do you do so much for me?"