The story takes place in a distant future world. In the society at that time, a group of races called "Equals" became the main productive force. Compared with ordinary humans, Equals are more perfect. They have beautiful appearance, noble moral sense, stable emotions, and smart minds, but at the same time, too much perfection makes Equals lose human emotions. The disease called SOS is the biggest unstable factor in this society. People with SOS will become sensitive, sad, depressed and impulsive. Once residents are found to have SOS, they will be exiled by the government and will never be able to return to society. Silas (Nicholas Hoult) is a patient with SOS. One day, he met a girl named Niya (Kristen Stewart). Although Niya seems indifferent and ruthless, in fact, she also suffers from SOS, and everything is just her disguise.