New York City.Melvin Udal, a irritable, prejudiced writer with obsessive-compulsive disorder, lives a regular and closed life.However, when his neighbor, a gay artist, Simon, was suddenly hospitalized and had to entrust his beloved dog to Melvin for care, Melvin's originally orderly world began to fall apart.Meanwhile, Carol, the only waitress who could tolerate his weird temper, was unable to continue working because she had to take care of her sick son, which made Melvin unable to even enjoy his favorite breakfast as usual.The inertia of life is broken, and the lonely soul is forced to face the possibility of change and connection.