Prosecutor Park Hee Joo(Tiffany Hwang), a righteous prosecutor who wanted to catch the criminal who killed her father. However, it showed up her father's murder is getting more complicated and soon the other prosecutors and polices who are in charge of this case closed it up as no evidence were found. But Park had promised her late father in front of her father's grave to avenge for him. She soon start the investigation herself and found out who is the killer. Park was shocked by what she found out. In the investigation, her good friend a reporter named Kang Ji Hoon helped her in her investigation. Her partners Ha Kyung and Jin Sung also helped her in the investigation. How will Park avenge for her late father? 

Cast:
Tiffany Hwang as Park Hee Joo
A brave girl who study like crazy and become a prosecutor to fight for justice. She born in single-parent family. She only had a beloved father who loves her very much but soon was murdered. She become a prosecutor to avenge for her late father. She had a friend who always there for her. And soon they be in a relationship as they found out they love each other.

You as Kang Ji Hoon
A friend of Park Hee Joo. He knows Park when they're 12 years old. He help Park a lot when she lost her father. His parents let Park stay at their place as she had nowhere to go until she is 22. He likes her then they slowly fall in love and in a relationship. He helped Park to investigate her late father murder case. Kang is a reporter and he works for the SBC and soon he was successful in his job and start his own show titled "The Truth Of A Person". He sacrifice very much for Park while investigating Park's late father's case.

Jo An as Lee Ha Kyung
A partner of Park. She is a detective. She used to help Park when Park needs help of a detective. They're friends in University. They had been investigated and prosecuted many cases. They closed a big case once and this helped Ha Kyung get promoted to a Chief in her inspection department group. With her high position, she helped Park to become the Special Prosecutor Of the DPO and finish off Park's late father's murderer. She's Lee Tae Sang's daughter.



Joo Sang Wook as Nam Jin Sung
A prosecutor at the DPO(District Prosecutors' Office)'s Inspection Department. Fall in love with Park but wouldn't dare to confess to Park. He helped Park a lot in her investigation too. He's not a guy who easily give up. However, if the goal is unreachable he had no choice but to let go. He fall in love with Park but Park loves Kang. So he let what to be what it is. 



Kim Young Chul as Lee Tae Sang
He's a politician who's background it's so dirty that no one could imagine. He used and killed many people around him and become more stronger. He killed Park's father. He was successfully ran away from his crimes. But he didn't know soon enough he'll get his punishment. His daughter was Lee Ha Kyung.