The Raven God

". . . an army of fire giants led by Surt gather in the Eighth Realm of Musspell . . . Orkney's only hope lies with Sam and his stalwart friends. As Surt prepares to launch his forces against Orkney, Sam and two of his fellow witches, Perrin and Mavery, set out on a journey to rescue Odin, aided by Skidbladnir, a magical ship of the gods that can fly over land and sea, and Geela, a Valkyrie who can transform into a battle-ready goose"--Provided by publisher.