When a software developer creates a dating app that a serial killer uses to find his next targets, she’s drawn into a dark world of romance and murder.

In 1994, on the first day that Yoo Yeul went on air as the new DJ of the popular radio show ‘Music Album,' a college girl Mi-su meets Hyun-woo who happens to drop by the bakery she works at. Like the music streaming from the radio, their frequencies slowly come in sync; even when they're apart, the show brings them together through ebbs and flows of events arising from both pure coincidence and inevitability, until the bitter reality sets in and drives them apart...

Renowned 70-year-old poet Lee Jeok-yo falls for a 17-year-old girl named Eun-gyo. Upon realizing his love for the teenager, the poet goes through emotional turmoil and self-destruction, while willing to give up his fame as one of the nation’s most respected literary figures. Involved in the love triangle is Lee's student Seo Ji-woo, a novelist in his 30s who also becomes obsessed with the girl.