- Title: 사자 (四子) / Saja
- Also known as: Four Children / Four Sons
- Genre: Mystery, romance
- Episodes: 16
- Broadcast Network: TBA
- Broadcast Period: TBA
- Air Time: TBA
- Original Soundtrack: Four Men OST
A female detective has lost a man she has loved. She meets a pair of twins and becomes involved in a mysterious case.
- Main Cast
- Supporting Cast
- This is a pre-produced drama.
- Filming was set to begin November 2017, however PD Oh Jin Suk walked away from the production on September 19, 2017.
- On October 17, SBS announced that PD Jang Tae Yoo would take over the project.
- Filming began January 2018.
- Nana was originally cast as the female lead, but left the production due to the numerous delays.