The Book of Names — D. Barkley Briggs

From an ancient land of myth and legend comes a cry for help.
Will two teenage brothers from our world find the courage to answer the call?

After tragedy strikes, Hadyn and Ewan Barlow must adjust to a depressing new life. But when a secret viking runestone opens the door to a world in peril, they are given a choice: join the battle of this magical, foreign land, or never find their way home again. In the Hidden Lands of Karac Tor, names are being stolen. Darkness spreads. As strange new powers awaken within, will the Barlows reluctantly answer the call to fight? Or will they succumb to Nemesia's dark spell and join the Lost...forever?