Anna, a dimension traveler, becomes a maid at the Roengrin Marquisate—infamously nicknamed the “Swan’s Grave”—to find a way back to her original world. There, she unexpectedly encounters Marquis Rothbart. Mistaking Anna for his missing wife, he forcefully takes her and makes an unexpected proposal: “Become my wife’s replacement.” He then tells her that in order to return to her original world, she must bear a child with someone from this world. While Anna struggles with the dilemma, Rothbart’s son, Swan Hilt, also hovers by her side, begging: “I want a mom, Anna.” A relationship with an inevitable end. A condition she cannot refuse. Desperate to return home, Anna ultimately accepts Rothbart’s proposal…