After several sick people are healed mysteriously, even beyond Gaius's mastery, Merlin follows his master who sneaks out at night and discovers the 'culprit' is old Alice, his beloved until she was chased during Uther's purge of magic. Merlin lets her have his room, but discovers she hides a vicious creature in a box, which Sir Geoffrey helps identify as the allegedly inexistent manticore. Gaius is hard to persuade. She nearly succeeds in killing Uther by poisoning a remedy Gaius prepares. Alice is jailed, and Merlin and Gaius must eliminate the monster.
—KGF Vissers