College student Kakeru is delighted to hear that he'll be joined for his preschool student teacher training by his own first love from preschool, Mizuki. To his dismay, when Mizuki shows up, she's not the sweet little girl he remembers, but a handsome guy. Kakeru is still in shock and even repulsed at the turn of events when during a conversation Mizuki tells him, "You were very special to me. You were my first love!" Will embarrassment and pride get in the way of their first love story!?