Daitokai ni Hoero

Jinnai, an enthusiastic cop is now at lost. First a gruesome murder case he's working on is assumed by people that it is a work of a demon. Then, his unit is getting help by a special agent sent by FBI to solve this case. What kind of special agent? An agent that specifically know how to handle Demon? Great! And that agent is just a high school girl? What does her unit called again? G-man. Things get more complicate when the witness of the crime is also a beautiful woman and now both of them fell in love with him. Jinnai tries to be strong but will he be able to resist them? Not to mention another G-man who fell in love with that high school girl? Will Jinnai handle all of this mess and solve all cases concerning demonic entity at the same time.