The opening of the interworld gates in 2018 created a host of problems. It became possible for criminals to hide in an infinite number of worlds. The discovery of the bodies of two adults and two children on the west side of Puget Sound in an uninhabited timeline by a yachtsman drove this problem home. The family had been murdered and their boat stolen. Problems had already arisen the year before with the appearance of warships from a timeline where the world had been made uninhabitable by a nuclear and biological war. Eve Cummings who had lost her legs below the knees in a confrontation with a rogue warship is given command of the frigate, Isaac Hull, and joins a task force headed for Hawaii. En route, a helicopter from her ship fishes a flier from the Pacific after his fighter plane crashes. The flier, Ron Madison, eventually becomes her husband.
The disappearances of small boats in an uninhabited timeline cause the Navy to assign Eve’s ship and two other frigates to patrol in the timeline where the depredations are taking place. Complications arise when interworld gates start opening randomly. Thomas Weston and his wife, Wilma, encounter one of the gates on a trip to Hawaii on their fifty foot sailboat, Albatross II and rescue two pilots who come through the gate and crash in the ocean. They eventually arrange to leave them off in their timeline of origin. Weston is given command of a research vessel that carries a group of scientists who are investigating the appearances.
The research ship departs from Portland, Oregon and takes a course toward the location of the gateway that Tom and Wilma had encountered the year before. Over the course of the following summer, they make a number of discoveries including people who can jump timelines without machinery. They also discover a couple of primitive civilizations in other timelines.
Eve’s pursuit of the pirates is interrupted by an assignment to escort a transport load of colonists who settle in an uninhabited timeline. A number of events flow from the efforts to set up the colony. Eve and the colonists also encounter the timeline jumpers. The appearance of the jumpers makes the location of the colony untenable, and it must be moved out of their range. With that settled, Eve resumes her pursuit of the pirates.
Eve pursues the pirates to a confrontation in which she allows herself to be taken hostage in hopes that they will release the people they have taken hostage. The encounter ends in a bloody confrontation between the pirate leaders.
The source of the random gate openings is found to be a world under bombardment by meteorites. The random openings are stopped, and a massive rescue operation ensues as survivors of the bombardment are transferred to other timelines. Tom and Wilma along with many scientists are witnesses to the destruction of all life on the version of earth struck by the meteorites.