V. E. Schwab opens another door to a new fantasy series set in the dazzling world of the 'Shades of Magic' series. Once, there were four worlds, each pulsing with fantastical power and connected by a single city: London. Until the magic grew too fast and forced the worlds to seal the doors between them. Now, a girl with an unusual magical ability comes into possession of a device that could change the fate of all four worlds. Her name is Tes, and she's the only one who can bring them together - or unravel it all.