Lost Girl (2010)

Season 1: Episode 10

While investigating a baffling sex-related murder case, Bo comes into contact with Saskia, a carefree Succubus who has much to teach her. But as they work together to find the serial killer Saskia reveals her true Dark Fae colours, which tests the limits of this newfound friendship -- and of Bo's own inner bad girl. Now feeling like a third wheel, Kenzi joins forces with Trick in a race against time to help him keep an old promise and save The Dal Riata.