- Drama: Bloody Heart / Red Single Heart (literal title)
- Revised romanization: Beulgeun Danshim
- Hangul: 붉은 단심
- Director: Yoo Young-Eun
- Writer: Park Pil-Joo
- Network: KBS2
- Episodes: 16
- Release Date: May 2 – June 21, 2022
- Runtime: Monday & Tuesday 21:30
- Language: Korean
- Country: South Korea
Lee Tae’s (Lee Joon) father deposed the king with the help of Park Gye-Won (Jang Hyuk) and his father became the king of a new dynasty. After succeeding his father, Lee Tae then became the next king. Lee Tae believes any action is justifiable to achieve his goal. He wants to rule as an absolute monarch, but First Vice-Premier Park Gye-Won opposes that idea. Park Gye-Won is even more powerful than the king.
Meanwhile, Yoo Jung (Kang Han-Na) is a daughter of a noble family. Lee Tae thinks of her as his wife. Due to that, her family gets involved in a power struggle in the royal court.