When a wealthy Manehattan socialite is murdered in her apartment with a gun, Johnny Northrain and partner Lyra Heartstrings are tasked by Princess Celestia to investigate. The case takes them from the high society of Manehattan to the city's underbelly in pursuit of gun runners and moonshiners. When the head of the gun runners turns out to be one of the most respected citizens of Equestria will they be forced to turn them in or let them go?

It all started when a pony turned up dead with an hour glass cutie mark. The investigation turned into a fight for survival against a Queen and her empire of Changelings. With the help of his partner, two Time Lords and a bubble headed Pegasus can Johnny Northrain stop the killings before it's too late or will the sins of his past force him to sacrifice everything for friendship and become the monster he's always feared?