Anna, a traveler from another dimension, enters the ominously nicknamed Lohengrin Marquisate—known as “The Swan’s Grave” as a maid, seeking a way back to her original world. There she unexpectedly encounters Marquis Rothbart, who mistakes Anna for his long-lost wife and takes her by force. He then makes an astonishing proposal: “Become my wife’s replacement.” Rothbart also reveals a shocking truth: for Anna to return home, she must bear a child with someone from this world. While Anna wrestles with the decision, Svanhild, Rothbart’s son, lingers near her, pleading: “I… I want a mother, Anna.” It is a relationship fated to end and a condition she cannot refuse. Determined to return to her own world at any cost, Anna ultimately accepts Rothbart’s proposal…