John Ringo’s “Black Tide Rising” series presents a world devastated by a bio-engineered viral plague. The plague destroys upper-brain functions turning the infected into mindless cannibals—effectively zombies. It’s highly contagious. It’s contracted through blood-to-blood contact with the infected—usually as they attack those not infected, to eat them. The series focuses on how survivors cope with the collapse of society.

“At the End of the Journey,” by Charles E. Gannon, is the latest arrival in the “Black Tide Rising” series. It follows the story of American teenagers who begin a senior year summer cruise aboard sailing ketch Crosscurrent Voyager just before the plague strikes. Sailing alone from the Galapagos to the South Sandwich Islands, they’re able to avoid the plague

This was related to an earlier novel, “At the End of the World.” In it, the ship’s ex-Special Air Service captain dies of a preexisting condition, but not before preparing his teenage charges to run the boat themselves and to fend off both the infected and those remaining human that mercilessly prey on the weak after society’s collapse.

As this sequel begins, the Crosscurrent Voyager’s crew hasn’t just survived, they’ve thrived. At Ascension Island, they pick up Royal Air Force senior aircraftman Halethorpe, who wants them to undertake a mission. The GPS navigation satellites are still working, but they’ll drift out of position, becoming useless—unless a software update is sent to them. GPS will make it significantly easier for Earth to rebuild from the plague.