Sim's Uncle Emmett is missing and on the run from the ruthless Council of Keys. Sim and his cousin Jeopardy are determined to find him. Their search takes them through a hidden door in time to Viking Norway and a desperate mission across land and sea to stop the legendary Gjallarhorn – said to herald Ragnarök, the end of the world – from falling into the wrong hands.
The Legend of Viking Thunder can be read as a stand-alone novel, or enjoyed as part of the thrilling Time Keys series. Follow Sim and Jeopardy's adventures in the series in Hunt for the Golden Scarab and The Impossible Gladiator.