"Since we can never go back to being just friends, us." Han Gyeom and Seoyoon, childhood friends who’ve never been apart for even a moment since birth, for 30 years. But their once unshakable bond crumbled overnight because of one reckless mistake. "I liked that day. Didn’t you, too?" "I…" They’re neither lovers nor just friends. Han Gyeom, who wants to keep this ambiguous relationship going, looked unusually bright today. "Make your choice. Either we go on like this, or we never see each other again." "If we can’t stay partners like this, are you saying we should cut ties completely?" Thirty years of friendship were hanging by a thread. Seoyoon’s face turned pale at the weight of those words. "Still confused? Then let’s check again." "Check what?" "Whether I can still be just a friend to you." The moment Seoyoon looked into Han Gyeom’s burning gaze, he realized with certainty— they had already crossed a river they could never return from.