Having reconnected with her biological mother and happy to be a future big sister, Rin is more centered and in high spirits. However, news of Nitani-san's potential remarriage has Daikichi (not to mention Kouki) in a funk. Seeing Daikichi like this concerns Rin, but it does nothing to prepare her for another shocking realization: She's actually jealous of Kouki's mother, who has inspired this kind of reaction in Daikichi. Troubled by these new feelings she has for her adoptive father, Rin finds herself trapped between her heart and her head. And when Kouki pieces together the truth, is Rin and Daikichi's quiet, happy existence headed for heartache?