Lee Jeno is a rookie police officer-the Chief's favourite rookie, at that. Na Jaemin is a rich, flirty teenage delinquent whose tribulations run much deeper than the surface. What starts out as a joke to Jaemin and a hassle to Jeno soon turns in to something so much more than either of them could've possibly imagined.

nana is a renowned serial killer in seoul, korea. nobody has caught them, they don't even know who it could possibly be. that was until detective in training lee jeno gives the case a try.