Desperate and on the run, Tillie finds herself in an uneasy partnership with Graeme McLeod, a daring adventurer who comes out of nowhere to thwart the Tuareg's attempt to kidnap her. Now the two of them are joined against angry Targui tribesmen, crocodiles, a sandstorm, rampaging hippos, and more as they embark on a quest that could bring them the answers they seek or cost them everything.