Hard Rain is the third book in the Vin Cooper series, following on from The Death Trust and A Knife Edge. Vin is a Major in the United States Air Force Office of Special Investigations, or as he puts it an internal affairs cop. Author David Rollins hasn't even given Vin time to heal from his last ordeal before thrusting him into another grueling investigation.

For his part, Vin Cooper has the very entertaining habit of turning on the wisecracks whenever he feels as though he is on the back foot. He wisecracks a lot.

Special Agent Vin Cooper was introduced in The Death Trust. In that book he investigated the death of General Abraham Scott in a glider accident in Germany. Two things were made quickly apparent, Cooper is a damn fine investigator and a major pain in the ass for just about every person with whom he comes in contact.

Vin, along with his OSI partner, Special Agent Anna Masters, have been assigned to Istanbul, Turkey for a hellish investigation after the US Air Attache to Turkey, Colonel Emmet Portman has been murdered in an exceedingly gruesome way.

The pair are quickly given the details of the case and a look at the crime scene and are left with very little physical evidence. However, they can see that whoever committed the murder was extremely organised, knew how to cover their tracks and had connections with the military. Their own investigation was going to rely on the co-operation of the Turkish homicide detectives, of whom Vin made the following observations:

The DS was five ten and built like a bag of dirty washing – narrow at the top, wide and round at the bottom. I pegged him as being around forty-five years old but he could have been older. He was sporting a dark brown comb-over, the kind that would make Donald Trump nod with admiration…his pants were hitched halfway up his rib cage, the belt cinched tight. And I hate to go into details, but he dressed to the left – and with what I couldn’t help thinking were a few pairs of socks stuffed down there for added stature.

Their investigation leads them into untold dangers after a second person connected with the case, and then a third, is also murdered. The streets of Istanbul are no longer safe for a couple of OSI investigators who are obviously better at their job than everyone anticipated. When witnesses continue to die and then Cooper and Masters are suddenly snatched off the streets the stakes are more real than they could have imagined.

Cooper and Masters have a history together – a romantic one as is documented in the earlier books. But all of that is over now and when Masters announces that she is engaged to be married to a JAG lawyer Colonel, the job reaches new heights in discomfort between the pair.

There is an irresistible charm in the childishness of Vin Cooper that puts you instantly on his side. The displeasure that he expresses over Masters’ news is done so in the most distinctive of ways. His repertoire of bad lawyer jokes is trotted out ad nauseum. This reaction probably best sums up the personality of Vin, adversity is greeted with a quip while true feelings are poorly hidden.

Set around one of the present day hot spots, the realities of modern warfare are laid bare including the aftermath of some of the weaponry used in both Gulf Wars. The question of the effects of Depleted Uranium (DU) weapons is examined in close detail as cover ups of monumental proportions, deep rooted hatred and the lure of the almighty dollar provide more than enough motivation for murder and cover up.

Hard Rain begins as a murder investigation but as is often the case, it is only the start of a deeply involving crime that is deeply rooted within the desolate Iraq desert. Cooper and Masters are up against someone who will think nothing of killing the both of them, the last thing they need is personal tensions to distract them from the case.