Megumi Nishijima is an attentive little brother who helps his divorced sister with her daughter, but he's cursed with the worst luck. In charge of his niece's daycare drop-offs and pick-ups, he exchanges daily pleasantries with her teacher, Tetta; a ray of sunshine with an adorable smile who is extremely popular with the kids, but just as klutzy as Megumi...! Megumi feels a sense of closeness to Tetta. And then, one day, they have a little "accident" that changes their relationship forever...!