And this time the battle is personal.
An ex al-Qaeda jihadi, Riz is now a fixer for a shadowy branch of the Ministry of Defence. He has teamed up professionally and romantically with Holly "Bang-Bang" Kirpachi - a hard-bitten girl gang leader.
Their marriage was set to be the social event of the season.
Until the wedding celebrations were interrupted by a series of murders in the East End of London.
Someone is copying Jack the Ripper with a new spate of gruesome killings in Whitechapel.
Riz and Bang-Bang are assigned to the case - but this is no easy mystery to crack.
Can they catch the killer before he strikes again?
Or are there other, darker forces at work?
'Kill Order' is an exciting police-procedural, techno-thriller that brings vividly to life both the new and the old East End. It is the third explosive installment of the Riz Sabir series.
"Absolutely rocks. Every line reeks with the raw authenticity of a writer who knows first-hand what the hell he's talking about." - Tom Cain, bestselling author of the Sam Carver thrillers.
'One of the most realistic depictions of how these operations work in real life. Forget about the "Hollywoodization" that seems to be the mark of most other books- this is the very real deal.' - Mubin Shaikh, counter-terrorism consultant and former covert operative, Canadian Security Services
Charlie Flowers is an author and an adviser on terrorism and extremism.
Kill Order was originally published as 'Blood Honeymoon'.
Endeavour Press is the UK's leading independent publisher of digital books.