In this world, everything is simple and clear – you can be in a relationship with anyone, but initially you are predetermined by who is your soulmate. How do I find him? There is a translucent red thread on each person's wrist, which only the person and his soulmate can see – it becomes brighter as you approach and breaks when you touch each other's hands, indicating that you have finally been found! Not everyone is looking for them, but your heart has always said that he is not so far away to miss this chance, so you were not too interested in a relationship with someone else if you find your true one before the time limit you set. "Thread stretched?" In the middle of the night street, you heard a man's voice and approaching footsteps, and when you looked down, you saw that your thread was bright red and stretched.