The first episode of this exciting two-parter sees King Uther captivated by his latest guest, the beautiful Lady Catrina (Sarah Parish). Prince Arthur is appalled by his father’s flirting but Merlin’s wary for a different reason – he suspects she is really a troll! Catrina and her strange servant Jonas (Adam Godley) are welcomed into the heart of Camelot and it is up to Merlin to prove she’s a monster and save Uther from ruin. Unfortunately, Catrina has her sights set on a far greater prize than the King’s heart. Can Merlin overcome her powerful troll magic before it’s too late?