Lately I've become disappointed with OCN dramas and I was hesitant to start this one. Now I'm glad I did though. The summary sounds like every other crime drama out there and I won't say it's different from others either. But in the end it depends on the script writing and the execution - and the acting, of course. So Jang Hyuk's and Lee Ha Na's characters team up to catch a killer that murdered their family members. Both of them work at the emergency call center. That doesn't sound quite thrilling now, but let me tell you that the producers did a great job to get you excited about it immediately. Because the Golden Time (the first hours after a crime occurred and is reported to the emergency center) is one of the most crucial parts in hopefully solving a crime or prevent worse ones (i.e. kidnapping cases). And what is special here, is Lee Ha Na's character's ability to hear more than others. Due to an accident she developed some kind of supernatural hearing that allows her to hear more than others - even through headphones. Right from the beginning the drama holds the suspense on a level that definitely makes your heart race. Fast camera movements and a good timing of scene editing ensure that. I can't say that this drama doesn't have any problems. It's still a k-drama and there are some flaws and again sometimes the police just looked stupid. You also have those characters who you want to punch because their behavior is so wrong when it comes to being professionals. But! There are also characters that I didn't like but who grew on me during the story, no matter that their behavior went into opposite directions. I also must admit that the story had some problems in the middle and lost some of its speed. I also think that the killer's identity was revealed too early in the drama which caused a big slow down as the story went a bit into some shady business themes. Although this doesn't mean that the killer's charisma wasn't engaging. He was a great psycho who gives you goosebumps. The whole acting of the cast was fantastic. From the leads to supporting characters to guest roles. Especially the latter. They captivated me during their short appearances in the drama and made every single case into something special. I never found them boring. They were thrilling and emotionally moving. At some point they were even more interesting than the main plot. The finale completely made up for the the middle part though. It picked up the speed and suspense again and let the drama end in an enthralling way.