In "Signal" the reason that Kim Hye Soo liked Jo Jin Woong was revealed.
On the 11th episode of tvN Friday/Saturday drama "Signal" (script Kim Eun Hee, director Kim Won Suk) broadcast on Feb. 26th, Cha Soo Hyun (played by Kim Hye Soo) prepared chocolate for Lee Je Hoon (played by Jo Jin Woong) of the past.
On this day, Cha Soo Hyun prepared chocolate for Valentine's day, but Lee Je Han who came back to the base talked about Valentine's Day said, "I hate women who give chocolate. They're just filled with these ideas." After hearing about that, she was disappointed.
Then, she thought back to when she was smitten by Lee Jae Han. The day that the congressman was supposed to come, she was making coffee. Lee Jae Han said, "You don't do investigations and only coffee? Are you some coffee girl?"
At this, she saw how he was taking care of her and touched her cheeks, as if she was smitten.
Meanwhile, "Signal" is about two detectives - one from the past and one from the present who communicate through walkie talkies to resolve long-time unresolved cases.