Dog trainer Li Zheng was once dumped by his girlfriend Wang Na. Three years later, Wang Na and her husband Liu Binbin come to his door with a 300,000-yuan Rottweiler named Qiuqiu. Qiuqiu has been on a hunger strike for three days, staring only at Wang Na's pregnant belly and drooling. Li Zheng asserts that it is waiting for the fetus to be born, but no one believes him. Qiuqiu disguises its gentleness, secretly learning to open doors and cut phone lines, and crawling outside the hospital ward window late at night. 72 hours later, it tears off its disguise and bites Wang Na. Li Zheng breaks through the door to rescue her, and the child is barely saved. After escaping, Qiuqiu attacks multiple pregnant women, and the police offer a 100,000-yuan reward in vain. It has locked onto a premature baby in the hospital incubator. To lure the snake out of its hole, Wang Na straps on a fake pregnant belly to act as bait in an abandoned hospital, and a showdown between human and dog unfolds.