A spoiled, rich and entitled brat is the title that Bae Joohyun, Irene, claimed. When she is forced to go on a business cruise with her sister Jisoo, and high class family, she feels nothing but dread with the claim; "waste of time". Obsessive and possessive with the thought burned into her mind, she can't help but question it when she meets an innocent and oblivious crew member, Kang Seulgi.

With a promise and grand plan to save her falsely jailed father and his company, Kang Seulgi, a robber who's wanted and on the run breaks into Bae Irene's house in the middle of the night for safety and search. With her home taken over by the charming masked stranger, Irene isn't sure if that's the only thing the thief has stolen from her.