Secret Agreement Oh! My Hottie

An erotic film about a younger sister who plots a murder due to her obsession with her older sister.

Jeong-eun and Yoo-jin, sisters who are living in a world where only the two of them can rely on each other, share a deep bond. When Yoo-jin receives a proposal from a kind man named Min-jae, she shares the news with her younger sister. However, Jeong-eun, who is obsessed with her older sister, hires a hitman, even offering her body, to break them apart. Upon discovering this, Yoo-jin offers herself as well to the hitman in an attempt to cancel the assassination request, but Jeong-eun takes it a step further and approaches Min-jae to hatch another scheme.