Jijo was declared fallow for one million years by the Migration Institute, in order to give it a chance to recover from successive colonies, but has been illegally populated by fugitives from several races seeking refuge there.

Kazzkark is a small planetoid, hollowed out to serve as a base for several of the Great Institutes, and a way station for travelers passing through nearby transfer points.

On the other end of "the Slope" a small group of humans attempts to quietly form a new settlement that may escape the murderous intent of the Rothen, but they find their Danik servants already there.

Back at the glade of gathering where the Commons of Jijo was in conflict with the Daniks, their differences suddenly become moot when a much larger starship lands directly atop the Rothen craft, imprisoning it in a quantum time-shifted substance.

The huge battleship is revealed to be operated by the terrifying Jophur, the supremely egotistical and violent form of the peaceful and kind Traeki that live on Jijo.

The reader, however, becomes aware they are aboard Streaker, the dolphin-crewed EarthClan ship not seen since the events of Startide Rising, some two years earlier in the series internal timeline.

They are accompanied by Mudfoot, known to Dwer as annoying "noor beast" but recognized by the Streaker crew as a Tytlal, a client race of the Tymbrimi, Earthclan's closest and most loyal allies, notorious for elaborate pranks.

Gillian Baskin decides to send the young friends into exile on a small island, for their own protection, but Alvin realizes at the last moment whose ship they have been on and demands to be allowed to stay.

As Streaker desperately flees towards the nearest hyperspace transfer point, Jijo's "Holy Egg" emits a powerful psychic blast that is felt by nearly everyone, and temporarily stuns the entire crew of the Jophur battleship.

The final installment introduces a new character, Harry Harms, the first neochimp to be selected to serve as a scout for the Navigation Institute, and new setting, the bizarre realm of "E-level hyperspace".

Harry detects unusual activity and eventually encounters Rety and Dwer, who had an improbable reunion aboard one of the decoy ships and wandered into E-level hyperspace due to their total lack of knowledge of space technology.

Streaker narrowly evades another ambush and manages to escape in the chaos, still pursued by Polkihjy, which is barely under Jophur control as it has been invaded by hydrogen-breathing life forms.

Lark, Ling, and the former Traeki sage Asx have all merged with one single gigantic life form now occupying much of the ship, which they simply call "Mother".

Dwer and Harry, now joined by a Synthian trader, rescue Rety from the cult and barely escape Kazzkark as space tremors tear it apart.

At the end of Infinity's Shore, a small group of neodolphins are left on Jijo, those suffering from "stress atavism", a condition wherein the subject reverts to a more primitive state similar to non-uplifted dolphins, as well as medical personnel to oversee them, and others deemed non-essential to Streaker's desperate final mission.

Additionally, they are to search for Peepoe, a nurse who was abducted by two reverted dolphins, Zhaki and Mopol, who wished to remain on Jijo with her as their unwilling sexual partner.

Using the dolphin's highly sensitive underwater hearing, he detects the sound of engines and, believing this may be one of the many ancient ships used as decoys during Streakers escape from Jijo, goes in pursuit of it accompanied by Chissis, a partially reverted crew mate.

She begins by swimming deep where her captors are less likely to notice her escape, but eventually resorts to a furious sprint across the surface once she detects the sounds of Mopol and Zhaki pursuing her with their powered sled.

Exhausted, she comes to a point where she is directly above the engine noise, and she makes a desperate dive down toward it, finding not a spaceship but something that looks like a strange sea monster that grabs her with a tentacle as she loses consciousness.

As they argue the point, Chissis suggests to Tkett that he listen more carefully to what Peepoe is saying, and he realizes there is a hidden sonar message behind her words advising him to "sleep on it".