Mask Wars — Joy Ellis

Nikki Galena is a tough detective inspector -- maybe too tough, because she has just been given a final warning. Her only hope is to team up with another loner, DS Joseph Easter, the man they call Holy Joe, in a bid to save her tattered reputation. As the two detectives try to find some common ground, the Fenland town of Greenborough is being terrorized by gangs of violent thugs, all wearing identical, hideous masks. Then a talented young student goes missing on the marsh and Nikki and Joseph find themselves joining forces with a master criminal in their efforts to save her. They need to look behind the masks, but when they do, they find something more sinister and deadly than they ever expected.