Galaxion is the name of a quirky little civilian scientific survey starship owned and operated by the Terran Space Association, and captained by Fusella Mierter (reputedly also quirky and little, but don’t say that to her face). As the story begins, TerSA has made a deal with rival organization Interplanetary Patrol, giving command of the Galaxion over to General Scavina Nelson and her team to test an experimental Jump engine.

The Galaxion has actually been refitted with the third version of these Jump engines. The second test run was made on the Pathfinder, Scavina commanding. That Jump resulted in a near-catastrophic collapse of the Pathfinder’s systems. The very first test run was attempted ten years ago on the Hiawatha, with the jump engine’s creator, Major Jeff Nelson—Scavina’s husband—serving as Chief Engineer. The Hiawatha was reported to have disintegrated as a result of the Jump, all hands lost.

Initially the success of the Galaxion’s own Jump attempt seems in doubt, because the ship appears not to have moved at all. However, three things become apparent that would suggest otherwise: first, some of the star patterns are different. Second, the Earth they find is not quite the same one they left. Third, they find the wreckage of the Hiawatha on this alternate-Earth.

The Survey Contact Team—Aria, Vessa, Patty, and new-guy Zandarin– is dispatched to investigate the wreckage and learn what has happened to the crew. Scavina, who is trying not to obsess over learning the fate of her husband, joins the Team.

Exploration of the Hiawatha uncovers more mysteries than answers. As the Team prepare to wrap up their survey, they have a violent encounter with the locals, resulting in a broken arm for Patty. They try to make their way back to their shuttle, only to run into yet another group of locals. These ones are armed. At gunpoint, they lead the Team into tunnels that lead to a whole tribe of people living underground in an abandoned subway. Also living here they find Carl Heraba, who Scavina recognizes as one of the Hiawatha’s missing crew.

Carl tells the story of how the Hiawatha’s jump led to a systems failure that forced an emergency landing, and how the surviving members of the crew were taken in by these locals whom he calls the Orehu. He also warns about the Rautani, another group whom he blames for the loss of nearly all of the survivors of the Hiawatha’s crash landing. He says the people who first attacked Scavina’s Team were Rautani.

Scavina has a private chat with Vanguarthe, apparent leader of the Orehu. With Carl acting as translator, Vanguarthe explains that the real threat behind the Rautani, and the reason why his people hide underground, are alien invaders called Miesti. He claims Miesti use some sort of mind control and have enslaved the Rautani and will do the same to anyone else who gets too close. Scavina infers that most of the Hiawatha survivors, possibly including her husband, are actually still alive and living with these Rautani. Despite Carl and Vanguarthe’s warnings, Scavina is determined to go find them.

While Vessa tends to Patty– who seems to have more wrong with her than just the broken arm– Aria has gone looking for a way to reach the surface. Zan has gone after her. She complains that her com unit has stopped working, and Zan, using her notepad and wrist alarm and several spare parts, kludges together a workaround. When they receive an alert signal from Vessa to return, Aria insists on sending him ahead while she tidies up the mess Zan has made. Just as she finishes up and is about to follow, she hears someone calling out in English. Thinking it must be another Hiawatha survivor, she goes to investigate.

When we next see Aria, she is in some sort of half-aware, drugged state. She hardly knows what’s happening, but it becomes apparent that she has been taken prisoner by the Rautani and Miesti. Even more bewilderingly, she seems able to understand them even though they aren’t speaking English.