Kidnapped by one of Seoul's most notorious mafia families, Eunmi is forced to nurse the injured mafia prince Lee Taemin back to health.    Afraid of the dangerous environment she finds herself in, she can't help but starting to warm up to the cold and indifferent man. 

Kim Min Ji is the daughter of the infamous Mafia Don Kim Dohyun, she's also his number 1. She asks no questions and does what's told of her. That is until the latest mark Jeon Jungkook comes into the picture. His caring personality unlike anyone  she's ever met before. She's set to take over "the family business" instead of her older brother Namjoon who instead runs the casino/club scene.       

Some time ago, a famed mega-corporation was exposed for fraud, corruption and countless embezzlements. Since then the heads of the company have all mysteriously disappeared, now their five sons who were once meant to become heirs the fortune are all leading very different lives. However, that changes overnight when all of them discover that on their necks are microchips, called keys, which have been forcefully attached to their skin. Strange text message

San is a merman in hiding and living among humans. But one fateful day, his identity is discovered and now he must fight for his survival and to protect his loved ones.