Jack Tenrec must stop a rampaging dinosaur from destroying settlements; during the adventure, he meets Hannah Dundee, the Wassoon science ambassador who has just arrived at the City in the Sea. Jack discovers that the dinosaur is being agitated by a sonic implant: he removes it, and traces it back to Governor Scharnhorst, who had it implanted in an attempt to turn the people against Jack and Machinatio Vitae when the dinosaur proved unstoppable. Their mutual distrust of Scharnhorst makes allies out of Jack and Hannah.

An earthquake scares up a herd of Triceratops, who then stampede down toward an assortment of settlements; after an argument with Scharnhorst about how to handle the problem (she wants to kill them), Jack and company organize a Xenozoic cattle drive. Despite poacher treachery, they manage to steer the herd to a safe ground and save the settlements.

Scharnhorst and Dr. Fesseden discover the control facility for an SDI ballistic-laser satellite, deep within Girth territory; this attracts the attention of both Jack and Hannah and the Poachers, and soon a three-way battle for control over the facility ensues. With a little help from the Grith, Jack manages to program the satellite to destroy the control facility, since this is the kind of 'knowledge' he believes everyone is better off without.

The Poachers launch a massive attack on Jack's Garage in an attempt to take it over and exploit its weapons and technical riches. Mikla poses as an escaped captive of the Poachers in order to infiltrate the Garage and sabotage its defenses. Jack's cleverness and the Poachers' lack thereof - foil the attack, and the Poachers are all driven back into the jungle, Mikla included.

Jack and Hannah notice a mysterious boy travelling with a pack of dinosaurs; Jack informs Hannah that he is being cared for by the Girth. Hannah nevertheless seeks the boy out when she sees him injured, and in the journey back to the City in the Sea, she (and Hammer the Poacher, watching nearby) witness his uncanny ability to control dinosaur behavior. When Jack takes Hannah to the Grith to discuss the importance of returning the boy, Hammer and company capture him, hoping to capitalize on his power. Jack and Hannah rescue him and Hannah reluctantly agrees to return him to the care of the Girth.

At an outdoor market run by the Moles, Hannah learns that Scharnhorst and Fesseden have accessed a high-tech cybernetics lab. When she tries to access the lab herself, she is captured by city guards; it takes Jack disguised as such a guard to liberate her. Fesseden activates the lab's dangerous tunneling robots, which seem to have minds of their own, and immediately make moves to break out of the compound. In the ensuing battle, Jack and Hannah elude Scharnhorst and, with the help of the Moles, bring the underground lab crashing down on the unstoppable machines.