The cliched plot of: Young orphan, who's really a king, is taken on a magical quest by a dizzy old man, who's really a mighty wizard to defeat the big evil dude and his unstoppable minions, as fortold by the prophecy. Along the way they join a group of miss-matched travellers including the spunky princess love interest (running away because she didn't want to marry the goofy/homely/evil/old noble with whom her parents were arranging a marriage), the gruff but loveable dwarf/barbarian, the mighty but tragically flawed warrior, the noble and perfect elf, the charming but roguish thief, the seemingly incompetant wizard apprentice who eventually becomes a great wizard, and the matronly old nurse-maid who keeps everyone in line. They are betrayed by one member of the party. Another member of the party (seemingly) dies, making the others resolve that much more to get the job done. The hero wins despite impossible odds, through his faith, honor, charm, kindness, bravery and other good qualities more so than through any actual skill or overt action taken. In the end, it's announced the hero's the King, and he can finally marry the princess.
Or any of the variations on that theme.
R.A.