So this JDrama is about murder mysteries involving locked rooms. Basically, there are murders that don't look like murders because the victims are in a 'locked' room and thus the murderer wouldn't have been able to escape from the scene after the murder. That's the crux of the mysteries.
I'm actually surprised by the pacing of this Jdrama. Because you'd think that they'd run out of locked rooms to solve because after all. How often do locked room type of murders happen? It actually is fresh and innovative each episode.
Although each episode follows the typical detective / sentai storyline. Where there's a murder, there's investigation followed by breakthrough. Despite the formulaic approach to the show - it's surprisingly well done and I really enjoyed it.
The ending song is by Arashi. The ending song is so damn good. I go doki doki for Arashi - no homo. So the show centers around the security otaku Enomoto Kei played by Arashi member Ohno Satoshi. All dramas that I've seen of Arashi are amazingly good. Not that I wasn't already an Arashi fanboy. I'm an even bigger Arashi fanboy after watching this show.
So the first episode you get introduced to the new junior lawyer. And she's... retarded. At the bank she sees a button and can't resist pressing it. Omg, are you 5?! She locks the lawyer in the bank vault and then the security otaku comes saves the day. Then... murder mysteries abound!
This show is really good because of the security otaku. And he plays the security otaku so well. It's like... otaku's are disconnected and slightly abnormal. While he's integrated into society and can communicate clearly. So cool and fun.
tl;dr - watch Japanese otaku sherlock holmes. And check out the amazing arashi video