Princess Mira of Vissel has come on a diplomatic visit to Lagrange, but as soon as she arrives, she wastes no time causing trouble-to everyone's surprise, she starts pulling Simeon with her everywhere she goes! Prince Severin and Julianne hurriedly summon Marielle to the palace to try and diffuse the situation, and when Marielle reluctantly investigates, she sees a shocking sight: Princess Mira is trying to seduce her husband! After that, strange things start happening around Marielle, including items falling on her in shops and even getting kidnapped! Could someone be trying to get rid of her? Tensions between the surrounding kingdoms worsen, stirring anxiety among the Lagrangians and casting a shadow over the future. But how is Marielle supposed to remain diplomatic when her marriage is in jeopardy?! This is the thirteenth volume in the adventures of the now-happily-married fangirl!