How can a mermaid from the Joseon era survive in modern-day Seoul? Shim Chung is a mermaid who finds herself transplanted to modern times. She is caught by Heo Joon Jae, a charming but cold con artist who is the doppelgänger for Kim Moon, the son of a nobleman from the Joseon Dynasty. But in the present time, Joon Jae works with Jo Nam Doo, a skilled conman who guides Joon Jae to become a genius scammer. But Joon Jae’s friend, Cha Shi Ah, who works as a researcher at KAIST, may be Chung’s only hope for surviving in her strange new world.

Awards Received at SBS Drama Awards :
- Top Excellence Award for Genre & Fantasy Drama (Lee Min Ho)
- Top 10 Stars Award (Lee Min Ho & Jun Ji Hyun)
- Best Couple Award (Lee Min Ho & Jun Ji Hyun)
- Special Acting Award for Fantasy Drama (Sung Dong Il)
- Best Eating (Jun Ji Hyun)

The Director's Cut version has extra 4 minutes scene for episode 1 and another extra 4 minutes scene for episode 2.  These scenes are not included in the regular airing of the drama.  A total of almost 9 minutes more compared to the regular version.