After breaking up with her trashy, good-for-nothing ex-boyfriend, Song Ayun gets a recommendation for a dating app from a friend. She starts chatting with a user called "Smiling Man" and even ends up having phone sex with him! However, something feels off—the Smiling Man's voice sounds strangely similar to her friend's older brother, Joo Sanghyun. Ayun checks the app and sends a message, just in case... and then Sanghyun's phone rings! Ayun initially believes she is safe because she assumes he has no interest in her, but as she watches Sanghyun pursue her with relentless, forward momentum, she realizes too late: This man is not safe at all!

Original Novel