All work and a little bit of fun. Roseanne Park, a rich, 27-year-old company CFO, isn't really one for emotional attatchments, the very reason why she never gets into serious, romantic relationships. How could she, when she's way too fond of the single, uncomplicated life? The night of her friends' engagement party at a luxurious night club in Uptown Manhattan, Rosie crosses paths with a fairly confident and attractive brunette, whom she learns, later on, to be Manhattan's oil heiress, Kim Jisoo. It was just supposed to be a friends-with-benefits sorta thing - not a single string attached - something Rosie made sure Jisoo understood, which she did. And as they went on with their strangely addictive, impossibly dangerous little game, lines between lust and love were drawn, stricly, by a certain rule Rosie decided would keep her in control of everything. However, when Jisoo seems to be a little too stubborn to keep her agreed promise, the highly-anticipated rich-people-drama starts.

A description is the only thing that lacks of the girl who, in Jisoo's eyes, already has everything. The beauty, the charm, and the heart that, despite being too big for her body, just can't seem to spare Jisoo a room.

When your "best friend" makes you realize that you've been crushing on your "roommate" for an unimaginably long time now, all kinds of games emerges at once, especially when you're too much of a coward to face the truth. Perhaps the solution to the problem would take a genius, and certainly NOT Kim Jisoo, who decides that the best way to get rid of that string of infatuation is by convincing Chaeyoung that she has a crush on Jennie Kim. And jealousy is an ugly feeling. It is, by far, the messiest game ever.

Chaeyoung never once felt happy living a princess' life. Given everything she's ever going to need, somehow, she feels like the pieces of her life are still impossibly out of place. When a mystery brunette gets invited by her bestfriend to her 18th birthday party as plus one, Chaeyoung finds herself oddly comfortable with the stranger's presence. Perhaps, even comfortable enough to agree to run away with her to Paris, where Chaeyoung finds the missing puzzle piece that would finally make the others fall into the right places.

Jisoo and Chaeyoung find out that their girlfriends are secretly hooking up behind their backs.