After the mighty battles of the first two episodes, which included The Great Dragon enforcing his own ‘scorched earth’ policy to save Merlin, life has settled down a bit in Camelot. But soon mischief is being made – and it’s Merlin’s fault. The young wizard has more time to get into trouble of his own making as he’s not scurrying around cleaning up messes caused by King Uther’s stubborn disenchantment with all things magical or protecting Prince Arthur when he gets into battles he’s not capable of fighting without the hidden help of Merlin’s magic.

It’s by pure accident that Merlin comes across a secret chamber and releases a mischievous goblin (voiced by Mark Williams – Arthur Weasley in the Harry Potter films). The goblin has a wicked sense of humour and some special powers. He takes control of Gaius’s mind and suddenly Merlin’s strait-laced mentor is developing a taste for all things gold, swigging ale and playing tricks on people.

Instead of acting like the court physician, Gaius is more of a court jester. King Uther, who has always been a tad vain, is suddenly bald and the whole of the Royal household is struck by severe flatulence – it’s like a trial arena for whoopee cushions. But all the frivolity is destabilising the kingdom and Merlin has to get the goblin gone before real damage is done.