Ten years ago, Daikichi spontaneously took in his late grandfather's love child. The passage of the last decade has seen him grow from an inexperienced caretaker to a dedicated guardian, though not without many struggles and the help of Rin, his ward. Now, amidst reuniting with her biological mother, preparing to welcome a baby sister into the world, and nearing the end of her time in high school, Rin slowly comes to the realization that she's started to see Daikichi, the man who is her father in all but name, in a romantic light. And when Kouki picks up on Rin's feelings and blurts out his discovery to Daikichi in an impassioned moment, will the damage done to Daikichi and Rin's cozy little family be irreparable?