According to reports on September 20, actress Lee Si Ah has been cast as the female lead Yeo Rin, the role previously held by Nana. Yeo Rin suffers the loss of her lover due to a mysterious accident, and while attempting to solve the crime, meets a man with an identical face to her deceased lover.�

'Four Sons', which halted filming back in May of this year, is seemingly picking back up at a slow rate, casting a new female lead as well as adding on a new PD.�