Inevitably, everybody gets hurt at some point in their lives. There are different remedies for different types of wounds, and as time elapses, these remedies start to become less effective. This is a story about a man who created a shield for his broken heart. Since the day his heart broke, he has been living inside a shell. To make it worse, he suffers from a specific type of allergy. Whenever he comes into contact with a human, he develops rashes all over his body and has trouble breathing. Because of this, he is forced to become a hermit and even start hating people. One day, he encounters Jo Ji A, a being unlike any other. At first, Ji A pretends to be a robot and tries to win Min Kyu's trust. Little does she know, she starts to fall in love with him. In addition, by interacting with her, Min Kyu slowly learns how to break out of his shell, love, and trust.