Thor's hammer is missing again. The thunder god has a disturbing habit of misplacing his weapon - the mightiest force in the Nine Worlds. But this time the hammer is not just lost. It has fallen into enemy hands. If Magnus Chase and his friends can not retrieve the hammer quickly, the mortal world will be defenseless against an onslaught of giants. Ragnarok will begin. The Nine Worlds will burn. Unfortunately, the only person who can broker a deal is the return of the gods' worst enemy, Loki - and the price he wants is very high.

By: Rick Reidan

Rick RiordanBorn in San Antonio in 1964,Rick Riordanstudied English literature and history at the University of Texas. He wrote the world-famous "Tres Navarre" series and swept three of the best mystery genres. While writing "Tres Navaru", he wrote "Percy Jackson and The Olmpians" at the request of his son. The 'Percy Jackson' series was made into a film from the 20th century Fox. He taught English to students between the ages of 6 and 8 in San Francisco Bay and Texas for 15 years, and he gained his knowledge of history and Greek mythology at school. He lives with his wife and two sons in San Antonio, Texas.