Pendragon

Can the young knights save the human world? King Oberon, the ruler of Avalon, is on the warpath and will stop at nothing in his quest to enslave the entire human race.

Rick and Roxy must escape back to Earth to rescue the only man alive who can help them fight Oberon—the legendary King Arthur Pendragon. Trouble is, Arthur isn't quite himself these days…for a start, he lives with a pet puffin called Peter and has no idea what century he's in!

Oh, and there's the small matter of some vengeful (and rather hungry) dragons to worry about.… The second book in the action-packed Young Knight trilogy.