Lynesse is the lowly Fourth Daughter of the queen, and always getting in the way. But a demon is terrorizing the land, and now she's an adult (albeit barely) with responsibilities (she tells herself). Although she still gets in the way, she understands that the only way to save her people is to invoke the pact between her family and the Elder sorcerer who has inhabited the local tower for as long as her people have lived here (though none in living memory has approached it).

It's been centuries since the robots of Panga gained self-awareness and laid down their tools; centuries since they wandered, en masse, into the wilderness, never to be seen again; centuries since they faded into myth and urban legend. One day, the life of a tea monk is upended by the arrival of a robot, there to honor the old promise of checking in. The robot cannot go back until the question of "what do people need?" is answered. But the answer to that question depends on who you ask, and how.

In the holy city of Tova, the winter solstice is usually a time for celebration and renewal, but this year it coincides with a solar eclipse, a rare celestial even proscribed by the Sun Priest as an unbalancing of the world. Meanwhile, a ship launches from a distant city bound for Tova and set to arrive on the solstice. The captain of the ship, Xiala, is a disgraced Teek whose song can calm the waters around her as easily as it can warp a man’s mind. Her ship carries one passenger.

In a corporate-dominated spacefaring future, planetary missions must be approved and supplied by the Company. Exploratory teams are accompanied by Company-supplied security androids, for their own safety. But in a society where contracts are awarded to the lowest bidder, safety isn’t a primary concern. On a distant planet, a team of scientists are conducting surface tests, shadowed by their Company-supplied ‘droid—a self-aware SecUnit that has hacked its own governor module, and refers to itself (though never out loud) as “Murderbot.”

War heroes aren't usually called out of semi-retirement and sent to the far reaches of the galaxy for a routine investigation. So when Colonel Carl Butler answers the call from an old and powerful friend, he knows it's something big - and he's not being told the whole story. A high councilor's son has gone MIA out of Cappa Base, the space station orbiting a battle-ravaged planet. The young lieutenant had been wounded and evacuated - but there's no record of him having ever arrived at hospital command.