"In Hyde, Jekyll, and Me" the important details of the kidnapping incident was revealed.
On the 10th episode of SBS Wednesday/Thursday drama "Hyde, Jekyll, and Me" broadcast on Feb. 19th, Yoon Tae Joo (played by Sung Joo) who had harsh feelings for Koo Suh Jin (played by Hyun Bin) lured Suh Jin into the House of Horror at the amusement park. Tae Joo was Lee Soo Hyun who had thought that he had lost his father because of Suh Jin.
Suh Jin was currently in another personality state, Robin. Tae Joo who didn't know this took Suh Jin to the haunted house where he didn't have great memories. Jang Hana (played by Han Ji Min) learned that Suh Jin was in danger. Hana then wanted to rescue Suh Jin and went into the haunted house. Then, receiving Tae Joo's call, he followed Suh Jin. Soo Hyun used Dr. Kang (played by Shin Eun Jung) whom he had searched for so long and started threatening Suh Jin.
The place that Suh Jin came was the place where Tae Joo and Suh Jin had been kidnapped as a child. Suh Jin left Tae Joo and left on his own. With that guilt, they created Robin, a personality that rescues people. This was the beginning of a double identity for Suh Jin.