V.E. Schwab 
This Savage Song 

Kate Harker and August Flynn’s families rule opposite ends of Verity, a grisly metropolis where violent acts summon real monsters: bloodsucking Malchai; clawing Corsai; and soul-stealing Sunai. The truce that keeps the families at peace is crumbling, and August is sent to spy on Kate. But when Harker’s men try to kill her and pin it on the Flynns, August and Kate find themselves running from both sides, in a city where monsters are real…

About the author

V.E. Schwab is the bestselling author of ten books including the Darker Shade of Magic series whose first book was described as ‘a classic work of fantasy’ by Deborah Harkness. It was one of Waterstones’ Best Fantasy Books of 2015, The Guardian’s Best Science Fiction novel, a Telegraph choice for the Best Young Adult Books of 2015 and Book of the Week for We Love This Book. The Independent has called her ‘The natural sucessor to Diana Wynne Jones.’