Ki Sihyeon is the only adult I don't have to tiptoe around. I don't have to be careful with him. He treats me like a kid—annoying, but he's not afraid of me. He's not weak. Seonwoo is a mental-type S-Class Esper, raised under strict surveillance and control at the Center. He was trained to suppress every emotion. Even when other Espers hurled insults or lashed out violently, he never retaliated. He simply followed orders. But in front of Ki Sihyeon, a fellow S-Class Esper and his teammate, keeping his emotions in check became a challenge. Sihyeon was the only one who ever treated him like a person. And Seonwoo had been in love with him for a long time. Yet Sihyeon already had someone. A sweet, kind guide named Yoo Sejin. Because of that, Seonwoo never even considered confessing. Then one day, Sejin ends up in a vegetative state after trying to save Seonwoo. Wracked with guilt, Seonwoo braces for Sihyeon's anger. But instead, Sihyeon says something cryptic. Then you'll have to take Sejin's place, kid.