Wang Dashu is a handsome bachelor. Because of his simple and upright nature, Dashu sometimes resembles a giraffe. Back when he was a chubby kid without the courage to confess his feelings, Dashu fell in love with someone. As an adult, he meets her again. This time, she is his roommate. Chu Zhihe is a sweet and kind girl. She is ambitiously waiting to meet the right guy in her life. When she reunites with Dashu, the difference in their personalities is stark. Lovable and precocious, the seemingly tiny Chu Zhihe seems like a squirrel next to the giraffe-like Dashu. Along with them are fellow urbanites Fen Ni, who always keeps her guard up like a panther, and Qin Hao, who hunts for a lady's heart like a wolf. As they struggle to survive in the jungle that is urban life, everyone begins to resemble some kind of animal. But even the strongest animal can drown in the river of life unless they grab on to the tree of love.