Lee Soo Hyun (Ji Jin Hee) can't seem to escape a haunting reoccurring dream about a woman from 1,000 years ago, so as the CEO of a gaming company, he uses that dream as the basis for an online game he calls "Lucid Dream." When Han Yun Hee (Lee Ji Ah), a part-time employee on leave from art school, reads the game’s script, she becomes unsettled as it coincides with her own dreams of a life filled with tumultuous romance. She finds she has an unexplainable connection to the game creator, but he is already engaged to a woman (Seo Ji Hye) desperate to keep them apart, and she is held back by another former flame (Ahn Jae Hyun), who continues to haunt her reality.
Duas pessoas são assombradas pelo mesmo sonho com um casal que viveu há milhares de anos. Será que um jogo online com essa temática poderá dar uma chance a esse amor?