Having lost his parents in a car crash, Yuuri is left to live in the mansion on his own. One day, a beautiful maid, Lilith, shows up, offering to work for him for free.

Tsukasa, a classmate of Yuuri's, is concerned for his well-being after having lost his parents.

Yuuri finds himself taking care of Lilith for once when she catches a cold.

Christmas is coming, and Yuuri and Natsume plot a surprise party for Lilith.