A poor young woman named Akane Kida and a wealthy but confined heiress named Reika Tōjō meet by chance and discover they are almost identical in appearance. Desperate to escape her life of poverty caring for her reclusive brother, Akane agrees to secretly swap lives with Reika, who is equally desperate to escape the suffocating constraints of her powerful family. Akane enters the Tōjō mansion as the wife of the eldest son Genichiro, while Reika begins a new, free life as Akane. The original story follows the romantic entanglements that arise from this switch: Akane finds herself drawn to Genichiro's younger brother Genjiro, while Reika grows close to Akane's brother Kazuma. Genichiro is revealed to have a mother complex and can only be aroused by women who resemble his mother. The first part of the story concludes with Genichiro divorcing Reika (replaced by Akane), Genjiro proposing to Akane, and Kazuma and Reika forming a bond, seemingly bringing the tale to a happy close.

The second movement, Daini Gakushō, opens with the appearance of a third woman, Shimomura Marie. Having learned of Genichiro’s peculiar preference, Marie spends a fortune on plastic surgery to make herself identical to the Tōjō matriarch and, by extension, to Akane and Reika. With the help of her younger brother Shugo, she orchestrates a scheme to infiltrate the Tōjō family and claim its vast fortune for herself. Unaware that Genichiro already has an ex-wife who looked like their mother, Marie is introduced into the household. However, the situation quickly spirals into confusion as the family, not knowing of Marie's existence, mistakes her for Akane. Genjiro, believing Marie to be his fiancée Akane, ends up sleeping with her, leading him to feel deep shame and distance himself from the real Akane, who is bewildered by his sudden coldness.

The narrative follows the complex and chaotic intertwining of these three identical women. Akane, heartbroken and confused, eventually learns of Marie's existence and takes on a disguised identity as a maid to infiltrate the Tōjō mansion and uncover the truth. Meanwhile, Marie, finding the weak-willed Genichiro a disappointment, shifts her predatory ambitions toward Genjiro. As Marie’s schemes deepen, she grows suspicious of those around her and becomes consumed by jealousy, particularly upon realizing that her brother Shugo has developed genuine feelings for the innocent Reika. The second movement is driven by a series of misunderstandings, with characters mistaking one lookalike for another, leading to betrayals, emotional turmoil, and a tangled web of love, desire, and deceit as Akane fights to reclaim her newfound happiness with Genjiro while Marie threatens to destroy everything to satisfy her own greed.