A chaebol cop joins forces with a gritty detective to take down criminals with a touch of wealth and a whole lot of wit.

'Monster Cop' Ma Seok-do investigates an illegal online gambling business led by a former STS Baek and an IT genius CEO Chang. Ma proposes an unexpected alliance to Jang and begins hunting down the criminals.

Gu San-yeong is possessed by an evil spirit after receiving a relic of her dead father. She meets Yeom Hae-sang, a folklorist who can see ghosts and spirits, and enters a completely different world from what she once knew.