The drama is about a man who commits suicide. A detective tries to solve the case and figure what really happened. The drama goes back in time to six months before the man, Lee Joon Soo, committed suicide. Yoon Hye Jin and Ha Dong Won's marriage is on the rocks. Though they have two daughters together, both have secret love affairs with other people. Joon Soo accidentally meets Hye Jin in Japan and falls for her. Hong Da Ae is the woman whom Dong Won is seeing on the side. She never wanted to be his wife nor his mistress and that is why their affair has lasted for so long. That was till Da Ae met Joon Soo. She realized that she could no longer continue seeing Dong Won and she fell for Joon Soo. Did Joon Soo really kill himself? - DramaWiki