The broken king - Philip Womack

The Broken King, the first book in The Darkening Path trilogy, is a thrilling fantasy adventure that takes its cue from Browning's poem "Childe Roland to the Dark Tower came." It tells the story of a boy called Simon who must search for and fight a terrifying enemy when his little sister is snatched away to a dark underworld. He is accompanied by Fiona, who has lost her brother in similar mysterious circumstances, and a strange, un-named boy who rescues them from a violent attack in the middle of the night. Instructed by a strange winged-deer messenger, they are told that together they must complete three tasks before they can enter the world of the Broken King to find them.