A time-traveling mermaid comes ashore to search for her past-life lover, but unexpectedly encounters a cunning con artist. A hilarious and dramatic cross-dimensional love story unfolds in Seoul. In the present day, Joon-Jae (Lee Min-Ho) is a smooth talking conman with magician like abilities. He works with Nam-Doo (Lee Hee-Jun) and Tae-O (Shin Won-Ho). For their next score, Joon-Jae impersonates a prosecutor and swindles a large amount of money from a wealthy suspect's mother. Joon-Jae then travels abroad and stays at an oceanside resort. Meanwhile, Sim Chung is swept up in a tidal wave and washed ashore near the oceanside resort. She sees Joon-Jae.