The pure and upstanding Momo Inuwashi absolutely adores her brothers, even to a fault! She's created a castle to protect them and would die to defend it. But...Tamaki Yugenji found a crack in the walls! Can he throw these siblings' lives into chaos and expose the terrible secret Momo is hiding even from her brothers? Find out how this 4-way romantic mess pans out in the new series, Momo's Iron Will!