After their father's death, Sun Hee and Do Hee have been living completely different lives. Sun Hee is known to be a fool due to her way-too-kind nature. On the other hand, Do Hee becomes a top stewardess and lives a fancy lifestyle. One day, something unpleasant happens to Do Hee.

Do Hee comes to Sun Hee's place and collapses. She asks Sun Hee for a favor, and Sun Hee decides to pretend to be her sister and goes to work. To make matters worse, she is forced to fly as well. During the flight, she saves the chairman of Donghae Airlines, Oh Pyung Pan, and even runs into the famous pilot, Song Woo Jin.

Sun Hee moves into the share house in place of Do Hee. There, she meets Woo Jin once again. He tries to close down the share house, and the two start to clash. She is shocked after finding out that her twin sister, Do Hee, likes him.

After seeing how furious Woo Jin is at her, Sun Hee gives up on Do Hee and his relationship and focuses on catching the culprit who attacked Do Hee. She finally finds a lead that will help her take one step closer to the culprit. Meanwhile, Ok Jeong suspects Sun Hee of committing adultery.

Sun Hee is once again attacked by the masked man in front of the share house. At that time, Woo Jin sees them and saves her. They go to the police station, and Sun Hee thanks him. Woo Jin tells her that if she is so thankful, she should move out of his house.

Woo Jin corners and questions Sun Hee about why she claimed that they were dating. Not knowing what else to do, Sun Hee tells him that it is because she likes him. Woo Jin, who has been getting strange feelings toward Sun Hee, is even more confused. Meanwhile, Sun Hee says that she cannot demand the flight attendant to hand in her resignation letter.