In 1930s Korea, during the Japanese occupation, a young woman named Sook-hee is hired as a handmaiden to a wealthy Japanese heiress, Lady Hideko, who lives in a secluded estate under the authoritarian rule of her uncle, Kouzuki. Unbeknownst to Lady Hideko, Sook-hee is secretly involved in a con with a swindler posing as a Japanese count named Fujiwara. The plan is to have Sook-hee help Fujiwara seduce and marry Lady Hideko, after which they will declare her insane, confine her to an asylum, and steal her fortune. Sook-hee's task is to encourage the heiress's affections towards the count while keeping her isolated from the outside world.

As Sook-hee carries out her role as a handmaiden, she grows unexpectedly close to Lady Hideko, and her feelings become complex. The intimate bond between the two women develops into a passionate affair which complicates the initial scam. Meanwhile, Lady Hideko harbors her own secrets and traumas, stemming from her ominous upbringing and the perverse demands of her uncle, who subjects her to reading erotic literature before an audience for his private library collection. The plot unfolds layers of deception, revealing that nothing is as straightforward as it seems, and everyone has hidden motives in the game of love and theft.