Chan, a successful businesswoman, ends up having a one-night stand with Key. Although Chan has no intention of taking things any further, the mischievous and charming Key boldly proposes that Chan keep her as her "kept girl." As time passes, what begins as an unconventional arrangement gradually blossoms into genuine love. But just as their relationship starts to flourish, Jay, Chan's first love, reappears, throwing their romance into turmoil.