The Liberator has just picked up the two surviving families in New York. Now they are going to rendezvous with Perry and any survivors he picked up. The ship makes contact with some helicopters that are following them. They claim to be from the surviving Federal Government. A meeting is set up on an island in the Potomac. There Captain Donovan meets the new President Harry Murphy. Murphy was the former speaker of the house and now under the line of succession the President. At first Donovan is glad that the government still survives. He is taken to Raven Rock an underground facility where the COG(Continuity of Government) is located.
It becomes clear that the current President is a power mad dictator. He is drafting all the citizens he captures into his COG. Including Percy who is captured in Georgia. He has plans to brainwash the crew of the Liberator. Luckily Donovan and Percy manage to break out with freed prisoners and escape. They make it safely to the sub and threaten to nuke Raven Rock if they try to stop them. The cowardly President backs down but vows revenge.
The final book in the series went out on a high note. They find the government run by a power mad dictator. We find out the white-shirts were created by a chemical C-210 that was used during the war and somehow mutated. A subplot is resolved on their home island with the dogs being captured and peacefully domesticated. Indeed the story ends with them requesting Liberator bring back plenty of dog food.
A good solid series with potential in exploring an entire planet and having kooky adventures among the survivors. But the Soviet Union collapses and most of these type series evaporated into the mists of time. Apparently the threat of nuclear war was gone and publishers scrambled for other ways to end the world. So we never do find out the further adventures of the U.S.S. Liberator as it cruises the world helping survivors.