Pure Heart

Pure Heart (순정, also listed as Purity or Soonjeong) is a 2001 KBS2 drama about Lee Chan Suk, a detective who is trying to track down a suspect named Kang Hyun Gee. In the course of the investigation, Chan Suk discovers that Hyun Gee has a biological sister, Han Sae Jin, who was given up for adoption as a child and grew up in a wealthy family with no knowledge of her birth family. He begins using Sae Jin as bait to draw her brother out, and the plan puts the two of them in each other's orbit far more than he expected. Over the course of the series, his professional interest in her turns into something personal, and he has to weigh that against the case he was assigned to close.

The supporting cast builds out the world around that central triangle: Yeom Jung Ah plays Lee Ho Sook, Son Tae Young plays Cha Da Hae, and Park Geun Hyung and Lee Jung Gil play the fathers on either side of the story, Lee Myung Sup and Sae Jin's father. Cheon Ho Jin and Son Jong Bum appear as fellow police officers working the same case as Chan Suk, and Sun Woo Eun Sook plays Hwang Soo Mi. Lee Dong Wook, early in his career at the time, is part of the supporting cast as Lee Ho Goo.

Pure Heart aired on KBS2's Monday-Tuesday primetime slot from September 3 to October 30, 2001, across 16 episodes, written by Lee Kyung-hee and directed by Jeong Seong-hyo and Kim Jeong-kyu. It came out the same year Lee Yo Won and Ryu Jin were both still building their drama filmographies, a few years before either became a more established lead. Beyond the broadcast record and the cast list, English-language sources say very little about how individual episodes played out or how the drama was received at the time, and nothing here fills that gap with a guess.