Always living in the shadow of his quest-loving older brother Fabious (James Franco), lazy Prince Thadeous (Danny McBride) settled to just smoke weed and getting in trouble with the women of the neighbouring dwarven kingdom. But when evil wizard Leezar (Justin Theroux) kidnaps Fabious' bride, Belladonna on their wedding day, his father gives him a choice - either aid Fabious on his quest to rescue his bride or be banished from the kingdom. As the brothers venture out to prevent an ancient prophecy from being fulfilled, they face betrayal from their own knights, danger and adventure which brings them to join forces with the fearless warrior Isabel (Natalie Portman), who has secret agenda of her own. When the traitorous knights return and imprison Fabious, Thadeous must step up become the hero in order to save his brother and the kingdom and win the heart of Isabel.