The boys gain an unexpected addition to their workforce with the arrival of Pythagoras's feisty younger brother, Arcas. Charged with escorting valuable cargo across the desert, the gang travels into the unknown with a ramshackle caravan of strangers, but one amongst them has something to hide. It isn't long before their journey takes an eerie turn danger closes in and a dark secret is exposed. Our heroes are forced to confront some uncomfortable truths as they fight for their lives under the desert sun.