Merlin Season 4 Episode 8 : Lamia

When the menfolk of Guinevere's home village fall victim to a mysterious illness, Gaius sends Merlin, along with Guinevere and the knights, to cure them but they are side-tracked by a waif-like girl, Lamia. Only Merlin and Guinevere suspect, rightly, that she is responsible and soon the knights fall under her spell, succumbing to the same sickness. Arthur rides out with Gaius,who has realised the girl's secret, but will they rescue Merlin and ...