Several times in the first two books of Tim Pratt’s Axiom Trilogy, characters mention the Vanir System, a human colony with which the other human polities have lost contact. No expedition sent to find out what happened to the colonists has ever returned. In the third and final installment, The Forbidden Stars, we finally discover why the Vanir System has been out of contact. The answer presents new challenges for Callie and the other crewmembers of the White Raven, as well as an escalation of their conflict with the Axiom.
As one would expect from the final volume in a series, The Forbidden Stars resolves several ongoing plot threads. One of these involves the Benefactor, a mysterious individual who’s been feeding the White Raven information about various Axiom facilities. In this book, the Benefactor sends an embodied AI called Kaustikos to accompany the crew on a mission. At first, it might seem like this steps on the toes of Shall, an established character who’s also an AI that often downloads itself into mobile robotic bodies. Pratt is careful to make Kaustikos’s personality and the appearance of his chosen body distinct enough that he doesn’t feel like just Shall 2.0.
Pratt also keeps up his record of introducing interesting and awe-inspiring technologies. The Axiom are played up as being almost godlike, walking advertisements for Clarke’s Law. There’s obviously a delicate balance to maintain in telling stories about such beings. If they don’t live up to their hype, readers will be disappointed. But if they’re too powerful, it will be hard to believe that the main characters could ever fight them effectively. Pratt keeps this balance nicely. When the function of the new Axiom technology discovered by the characters at the beginning of the book is revealed, it’s almost literally gasp-inducing. But because most of the Axiom are still in suspended animation, the conflicts faced by the crew are on a more manageable scale.
I do have one minor plot-related quibble. At one point, when Callie and company are in a bad situation, we discover that Callie had planted some devices to thwart the villains in such a scenario. While this is entirely in character for the intelligent and suspicious captain, it wasn’t foreshadowed at all, so it seemed to come out of left field.
I would have been happy to see the Axiom series continue, but The Forbidden Stars does bring both the overall narrative and individual character arcs to satisfying milestones. The trilogy was a fun ride and makes me eager to seek out more of Pratt’s work.