Erak's Ransom

Erak's Ransom is the seventh thrilling book in John Flanagan's Ranger's Apprentice series – over eight million sold worldwide.
In the wake of Araluen's uneasy truce with the raiding Skandians comes word that the Skandian leader has been captured by a dangerous desert tribe. The Rangers – and Will – are sent to free him.
But the desert is like nothing these warriors have seen before. Strangers in a strange land, they are brutalized by sandstorms, beaten by the unrelenting heat, tricked by one tribe that plays by its own rules, and surprisingly befriended by another. Like a desert mirage, nothing is as it seems. Yet one thing is constant: the bravery of the Rangers.
Perfect for fans of J.R.R. Tolkien's Lord of the Rings, T.H. White's The Sword in the Stone, Christopher Paolini's Eragon series and Rick Riordan's Percy Jackson series.