The building matters because the memories in it are the only thing keeping this fractured family from falling apart. A demolition notice becomes permission to finally say what three years of living together couldn't, that Mitsuki needs her mothers, that Chitose needs her daughter, that the home they built was never about the structure. You watch them choose each other one last time, and it lands because the show earned it in every quiet moment before.

When Mitsuki learns that her high school plans to tear down its old building, she is saddened to think of how many memories will be lost along with it. Chitose and the rest of the moms take action and try to stop the demolition. Along the way, Fumitsuki, Chitose and Mitsuki at last come to understand their true feelings. Told across three OVA episodes, this final chapter of Happy Lesson blends comedy and romance.