Based on the humorous Norse tale about the theft of Thor's hammer, Bruce Coville fleshes the story out with other pieces of Norse mythology to give readers this amusing story of cross-dressing gods, talking goats, and dopey giants.
Told by Thor's goat boy Thialfi, Thor's Wedding Day begins with Thor discovering his mighty hammer, Mjolnir, missing. His trickster brother Loki discovers that their enemies, the giants, have somehow gotten hold of the hammer and refuse to give it back unless their sister, Freya, marries Thrym, king of the giants and Thor's enemy. Freya refuses, and Loki concocts a scheme to dress Thor up as Freya and get his hammer back. Loki agrees to accompany Thor as a bridesmaid and Thialfi must dress up to be Thor's goat girl. While in the company of the giants, Thialfi discovers that their plan goes far deeper than just handing Mjolnir back to "Freya" after the wedding, and he finds himself in the position of saving Asgard.