Disguised under the shadows of a mask, a crew of desperados band together under the leadership of a criminal mastermind known only as “The Professor” to pull off the biggest heist Korea has ever seen.

Love Alarm is an app that tells you if someone within a 10-meter radius has a crush on you. It quickly becomes a social phenomenon. While everyone talks about it and uses it to test their love and popularity, Jojo is one of the few people who have yet to download the app. However, she soon faces a love triangle situation between Sun-oh whom she starts to have feelings for, and Hye-young, who has had a huge crush on her.