After Operation High Jump in 1947 finally discovered and captured the main Nazi cave entrances to the Hollow Earth (the original entrances in the salt mines of Bavaria being dynamited shut in 1945) the Allies are finally exploring the lush jungles of Middlehiem, in search of the two divisions of Nazi troops and untold concentration camp slave labourers who disappeared into the underworld in 1944-45.
The charming log chalets of Nieu Deutschland were made with slave labour....
With mainland Europe devastated by the Z-Virus, and much of Eastern Europe still quarantined due to hordes of wandering undead, there is an eye to colonizing the Hollow Earth.
But first, threats must be neutralized. Without the ability to use air support or heavy vehicles, Allied light infantry troops must fight their way through the caves and jungles of Middlehiem. Giant beasts, dinosaurs, and primitive tribes are not the only horrors they must face.
The armoured Bren suits are well adapted for exploring the dangers of Middlehiem...
The Nazis have brought many of their most deadly weapons with them: werewolf soldiers, light mecha and psychic troops wielding alien tech. Warfare tends to be on a small scale; scout squads and light infantry recon platoons clashing in the remote jungle far from support, or battling in claustrophobic cave systems.
The Soviets, wary of their erstwhile allies, are also energetically staking claim to the underworld, through their Tunguska entrance.
Their vaunted sniper teams are very useful for dealing with rogue dinos, and they use anti-tank rifles to good effect.
Already cracks are appearing between the old allies - there have been clashes between British and Russian troops, and their is talk of a "Cold War" as the Soviets attempt to establish a new Communist empire.