The series is an original take on the events and the aftermath of the World War II period of history and Britain's fight against Germany and Russia.
Set over 20 years after the events in Bitter Seeds, Europe is a vastly different place, Russia is the controlling entity and an uneasy truce remains in place.
Gretel and Klaus, for me the two outstanding characters from the first novel have been prisoners for 20 long years in Arzamas-16, a large and heavily guarded research facility, a secret city formerly known as Sarov.
The Russians have reversed engineered the Götterelektron (battery powered) technology and made massive strides improving there 'supersoldiers' to eclipse anything the Nazi Doctor Von Westarp's Reichsbehörde project could produce.
Incarcerated for 20 years its finally time for Gretel to initiate their tricky escape and restart the gears turning to bring all her plans to bear as they make their way to Britain. During these events Klaus has been growing in awareness of what Gretel is capable of, he realises with horror that she talked Heike into suicide all those years ago simply to use the glass jar that contained part of her brain as a glass for the guards to get drunk and aid in their escape. The sheer callousness bought new depths to Gretels amazing foresight and the insight into his sister brings a fear to Klaus like nothing before.
Raybould Marsh, the former British spy, is now a broken down middle-aged man with his marriage hanging by a thread and a depressing life with nothing to look forward to. Flitting between jobs, he works as a gardener, fuelled by alcohol and a temper that keeps getting him into trouble. His wife Liv seeks escape but they are bound by a son who is mentally ill, a child without a soul. As Gretel and Klaus reach London, Marsh is called from his enforced retirement to once more serve his country and serve he must as he is vitally important to Gretel's plan.
The warlocks are dying, a mysterious assassin who deals death that looks entirely natural, the Milkweed team has a traitor and once more Gretel whose aim is now seemingly to assist the government pulls the strings and the traitor is caught on film but to what ends.
A stunning read, Tregillis raises the bar with The Coldest War, a tension filled jaunt with some surprising twists and turns. All the characters are excellent but once again Gretel steals the accolades and as her plans slowly reveal it is captivating and fascinating. She is one of the most memorable female characters in all the books that I have read, incredibly realistic, devious in a spine chilling way.
Gretel's ability is the power of precognition and her plans revolve around what she has seen but these plans have taken seed right from the start of the series and the author skirts around this wonderfully, never quite revealing enough until the end. And the ending is done superbly, can Gretel manipulate the future or simply delay the inevitable.