When Akito Sanada reaches 16, a mystical red thread materializes on his left ring finger, allegedly linking him to his soulmate worldwide. However, Akito's thread leads to his classmate Riran Kuonji, sparking frequent clashes between them. Despite this unusual connection, their bond remains strained, each convinced of the other's disdain. Thus begins a bittersweet romance between a graceful yet awkward girl and a somewhat oblivious boy.