When Merlin comes across a secret chamber, he accidentally releases a goblin. The mischievous little creature possesses Gaius, making the wise and renowned court physician turn into a shadow of his former self, quickly developing a taste for gold, ale and magical jokes. To make things worse, the king suddenly becomes bald and a nasty scourge of flatulence hits the royal household. Will Merlin be able to figure out the source of all troubles, return the gobblin back to where he came from and put an end to the havoc before any real damage is done?.
Merlin is a young warlock who arrives in the kingdom of Camelot after his mother arranges for him to stay with the court physician, Gaius. He discovers that the king, Uther Pendragon, has outlawed magic and imprisoned the last great dragon deep under the kingdom.
The dragon tells Merlin that he plays an important role: to protect Uther's son, Arthur, who will bring forth a great kingdom. When Merlin meets Arthur, he believes that he is arrogant and Arthur, likewise, views Merlin as subservient. Merlin must keep his magic secret or face being executed by Uther.