In an orphanage, a withdrawn boy who rejects everyone finds himself drawn to a persistent child who refuses to leave his side. He names him “Only One” and becomes increasingly possessive, determined to keep him close. Yet fate repeatedly threatens to tear them apart. Even after surviving countless crises together, they are separated once more when Only One awakens as an exceptionally gifted all-round Guide. Refusing to let him go, he sets out to reclaim the person he considers his alone.