Gyeongseong, 1945. In Seoul's grim era under colonial rule, an entrepreneur and a sleuth fight for survival and face a monster born out of human greed.

A woman with only a short time to live and a man with the supernatural power to bring the world to an end discover the true meaning of life and love.

Tells the romance story of a girl named Hye Ri. She goes to Gangwon Province on a graduation trip with her friends. There she meets a mysterious man Woo Hyuk who runs a guest house. She gets attracted and closer to him and decides to name him “the mermaid prince”.

Han-joon has been in love with his childhood friend, Yoo-jae, for a long time. He knew his feelings wouldn’t be reciprocated, and it didn’t matter because he never even dreamed of confessing to him. But this time, he wanted to express his love.

Pyeon Mi Jo is an immortal woman who does not wish to fall in love anymore. Nearly a thousand years old, her experiences in love tells her all men are "bastards" one way or another. But what's her current job? A Love Counselor. One day, she gets a new noisy neighbour, Yoo Joon Woo, a hip-hop crew leader.