Gillian 
Icefall [EPUB ebook] 

Death stalks Seth Mac Gregor’s clan in their otherworld exile. Kate Nic Niven is close to ultimate victory, but still needs Seth’s son Rory, and his power over the Veil. And she’ll go to any lengths to get him. Meanwhile, survival for his loved ones seems all Seth can hope for. But might a mortal threat to his niece Hannah force him to return to his own world to challenge Kate? And will Rory go with him? Because he suspects there’s a darkness trapped in the Veil, and that it wants to get out. Nobody gets forever. But some are willing to try…