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.

The Hygrometric Dehabitation Region, or the "Zone," is a growing band of rainforest on the equator, where the heat and humidity make it impossible for warm-blooded animals to survive. A human being without protection in the Zone is dead in minutes. Twenty years ago, Marks went into the rainforest with a group of researchers led by Doctor Elaine Fell, to study the extraordinary climate and see if it could be used in agriculture. The only thing she learned was that the Zone was no place for people. There were deaths, and the program was cut short. Now, they're sending her back in.

Ever since she was cursed by a faerie, Theodora Ettings has had no sense of fear or embarrassment—an unfortunate condition that leaves her prone to accidental scandal. Dora hopes to be a quiet, sensible wallflower during the London Season—but when Elias Wilder, the strange, handsome, and utterly ill-mannered Lord Sorcier, discovers her condition, she is instead drawn into peculiar and dangerous faerie affairs.

Idris has neither aged nor slept since they remade him in the war. And one of humanity's heroes now scrapes by on a freelance salvage vessel, to avoid the attention of greater powers. After Earth was destroyed, mankind created a fighting elite to save their species, enhanced humans such as Idris. In the silence of space they could communicate, mind-to-mind, with the enemy. Then their alien aggressors, the Architects, simply disappeared - and Idris and his kind became obsolete. Now, 50 years later, Idris and his crew have discovered something strange abandoned in space.

Civilization has fallen. The solar system is blanketed with the automated weapons of ancient wars, engineered plagues, hazardous waste, rogue AI, monsters from outside our dimension, artificial disasters, and nuclear climate change. Every moment of life on Earth is a brutal fight for survival. The people of Sol carry on, but hope is at a premium. They need something more. Someone with a plan, a savior, a hero. What they get is Lily.