Nimueh forges a poisoned chalice and plants it at the royal table where Arthur is to drink. Then Merlin is force to drink the poison and becomes ill. Arthur disobeys his father and leaves to find the cure for Merlin, but his is heading for a trap.
A monster attacks Camelot, and Arthur is bitten by it before Merlin slays it. Arthur sinks into a coma and Merlin can only save him by going to the Isle of the Blessed. Merlin meets the witch Nimueh, who gives him the antidote. Can she be trusted?
