After separating from her husband, momo isshiki has been living with her son yugo. She worked hard to raise him, and he grew up to be a healthy student aiming for a top university. Their hardships were supposed to pay off, and a happy life awaited once yugo became a working adult. However, during a summer career counseling session with his teacher takamoto, just before yugo's graduation the following year, momoko was left alone in the classroom and told that there was a problem with yugo's college entrance.
