Merlin and Arthur find themselves vastly outnumbered in a tavern brawl, but an enigmatic young man helps them to victory, as the fantasy drama continues.

The stranger, Gwaine, risks his life to protect the Prince and is seriously wounded in the process. Arthur takes him back to Camelot where he quickly makes a recovery and gets to work: drinking, charming the ladies and causing trouble for Merlin - who has been charged with looking after him.

But when what appears to be two unscrupulous knights try to kill the Prince, can Merlin and the inscrutable stranger stop them before it is too late?