The war is coming to a dramatic head. The Soviet Underground City and Underwater City have agreed on an alliance. Their Island Class submarines will bomb the German City with their missiles while the Underground land forces will then assault it. Rourke and his allies come up with a desperate plan. They will send a commando force to capture the Soviet submarines. Then use them against the land forces.
The story is coming to a conclusion. They end with a great victory and are on the verge on assaulting both Soviet cities. There is another ominous development in the Nazis are still causing trouble. They stage an attack on the German city so this does hint at future troubles with them down the road. This is the last book in the second story arc and next book will have a lot going on. Something completely unexpected and a whole new chapter in the Rourke family adventure.