This episode depends very much on how attractive you find Joan Jett, the former lead singer of the 'Runaways,' and solo singer in her own right with her group, the 'Blackhearts.' The anthem, 'I love rock & roll' is a classic of her generation.
Joan wanders into the story as her first group sing, 'Cherry Bomb' as backing music, sadly, it goes downhill from there. There's a gratuitous scene with her in just a tight, skimpy, black camisole/teddy but that can't hide the poorness of the actual episode. As yet more immortals fight over who has the right to be 'the Only One.' For a small clan, there's seems to be an awful lot of these immortals...Joan is yet another one and is a wolf in sexy clothing as she tries to seduce Ritchie over to the 'dark side.'Who seems to be enjoying the journey very much! Surviving an final sword encounter with Duncan, seems to indicate her to be a returning character.
Joan is no actress but then again, neither is anyone else in this, so, it doesn't really show that much. Joan's New Jersey accent is surreal to hear alongside Duncan & Tessa's attempts at French tinged English.
As mentioned, if you like Joan Jett and find her tom-boy, bad girl look an attraction, then it's worth a watch. For everybody else, it's very run of the mill, TV series grist to the mill fodder.