Inconstant Star
by Poul Anderson
There are two parts to the novel, 'Iron', and 'Inconstant Star'.
In “Iron”, Saxtorph and the Rover, hired by the wealthy Crashlander Laurinda Brozik, set out to explore a newly discovered red dwarf star. When they arrive, they are challenged by a Kzinti warship. Separating the crew onto the shuttles, the Rover is captured and landed on one of the moons. The first shuttle sets on Prima, the first planet, and is held fast by a planet-sized organism that begins dissolving the shuttle. They broadcast for rescue, and are refused help by the Kzin.
Meanwhile, helpless to rescue their friends, Robert, Dorcas, and Laurinda make a plan to steal a tug and escape back to friendly space with the news of the Kzin base. Dorcas pilots the tug, and takes out the ship guarding the Rover. Robert and Laurinda land, fight off a Kzinti shuttle, and recover the Rover. They are able to rescue Juan and Carita, and destroy the base with a guided asteroid.
In “Inconstant Star”, Saxtorph and crew are hired by Tyra Nordbo to redeem her father's honor, as he was accused of collaboration with the Kzin during their occupation of Wunderland. To do so, they must use notes he had left behind and follow a ship that had left 30 years prior to investigate a concentration of gamma rays. They travel to the coordinates, and find a massive artifact made of an unknown metal. A hole in the spherical artifact is pouring out lethal radiation. As they study it, they learn it is a weapon of the Tnuctip. It is a shell around a “captured” black hole, one that had been holed by a meteorite and is thus releasing the Hawking radiation. They then deduce the route of the original Kzin ship, and head off to the Father Sun, the star of the Kzin homeworld. En route, they locate the Sherrek, where Tyra's father Peter had worked free of his Kzin captors. They rescue him and head back to the artifact. Another Kzin ship, Swordbeak, also finds the old ship. They, too, head to the artifact, and catch the Rover by surprise. Just when all looks lost, Robert and Dorcas conceive a plan to use the artifact's radiation against the Kzin warship. In a last act of defiance, a dying Weoch-Captain activates the artifact's hyperdrive and heads out into unknown space.