Geraldine McCaughrean 
White Darkness [EPUB ebook] 

Captain Titus Oates, hero of the Antarctic, has been dead for nearly a century. But not in Sym’s head. In there, he is her constant companion, her soul mate, her adviser. It is as if he walked out of the Polar blizzard and into her mind. In fact, if it were not for Titus, life might be as bleak a place as the Antarctic wilderness. When she is taken on a mystery expedition by her eccentric uncle Victor, Sym can’t believe her luck. Destination Antarctica-the very place she’s always wanted to visit. But Victor has other plans, more sinister than Sym could possibly imagine. Stranded in the most isolated part of the world with her trust in someone she comes to realize is a madman, she must find a way to avoid a gruesome fate. But what should a teenage girl do? Could it be that Titus, the one who perished in that very place, will be the means of her survival?