An interstellar craft is decelerating after its century-long voyage. Its destination is V538 Aurigae - a now-empty planet dominated by one gigantic megastructure, a conical mountain of such height that its summit is high above the atmosphere. The ship's crew of five hope to discover how the long-departed builders made such a colossal thing, and why: a space elevator? a temple? a work of art? Its resemblance to the mountain of purgatory lead the crew to call this world Dante. In our near future, the United States is falling apart. A neurotoxin has interfered with the memory function of many of the population, leaving them reliant on their phones as makeshift memory prostheses. But life goes on. For Ottoline Barragão, a regular kid juggling school and her friends and her beehives in the back garden, things are about to get very dangerous, chased across the north-east by competing groups, each willing to do whatever it takes to get inside Ottoline's private network and recover the secret inside.