The Girl in the Box, Book 51
(Paperbacks available on Amazon in US/UK/EU)
Sienna Nealon returns to Nashville after a six month absence to find everything has gone straight to hell. Among the problems waiting for her are street gangs run amok, and after an incident at a mall, local officials are desperate for a solution to the violence.
Unfortunately, Sienna's arrival heralds more violence, not less, and soon she's in a race against time to stop a gang war before the fallout destroys the whole city.