Volume 10 is the tenth volume of Fruits Basket.
Tohru Honda, Momiji Sohma, Yuki Sohma, Kyo Sohma, and Hatsuharu Sohma are spending summer vacation at the Sohma vacation house. The start of the book has the group at the beach. Yuki, Kyo, and Hatsuharu comment on swimming and Tohru. Watching Tohru makes Yuki remember his childhood. Meanwhile, the other Sohmas are receiving the invitations to the vacation house. Kisa thinks it's wonderful while Hiro Sohma says things like "Why would he want us to go on vacation with those guys", and "Why's he so giddy? Isn't he in high school now? And what's with the rabbit stationary? Does he think we're in kindergarten?" While this is going on, Hiro notices Isuzu Sohma walking angrily past his house.
Back at the vacation house, Yuki develops a small fever as a result of winning a swim contest. He plays with Tohru's hair and says that he, "will someday open up that tightly closed lid".
The next day, Hiro and Kisa arrive. Afterwards, they try to catch 'stag' beetles. Tohru accidentally dropped her wallet with her mother's (Kyoko Honda) photo in it. Hiro returns it and tells her that she always thinks of her mom and nothing else, causing Kisa to cry and scold him. He then realizes that he is losing points with Kisa for his attitude. The next afternoon, Hiro tries is best to behave, even though Kyo can tell he has done something to Tohru.
Mayuko Shiraki and Shigure Sohma are having a conversation on the topic of romance. Mayu assures him that there in nothing romantic between them, and then reminds him about when they used to date. She keeps criticizing him for not showing affection and just being there.