Kell is one of the last Antari — magicians rare enough to travel between parallel versions of London, each bound by walls no one else can cross. There is Grey London, ordinary and magic-starved, ruled by mad King George; Red London, his own home, vibrant and balanced in its power; and White London, starved and vicious, fought over by a pair of siblings who will do anything to seize more. A fourth London, Black, was lost long ago to a magic that consumed everything in it.
Kell serves as an ambassador between the surviving Londons, but he also smuggles forbidden trinkets between worlds for his own amusement — until one deal goes wrong and leaves him holding a stone of impossible, black magic that shouldn't exist. Fleeing for his life, he collides with Delilah Bard, a cutpurse and would-be pirate from Grey London who robs him first and demands answers second. Reluctant allies, the two must outrun assassins from every London to keep the stone from unleashing a magic that could destroy them all.
V.E. Schwab's A Darker Shade of Magic opens the Shades of Magic trilogy with a richly imagined multiverse, brisk swashbuckling adventure, and a slow-building partnership between a guarded magician and a fiercely independent thief.