"Lost Girl" follows supernatural seductress Bo (Anna Silk), a Succubus who feeds on the sexual energy (sometimes called "chi") of humans. Growing up with human parents, Bo had no reason to believe she was anything other than the girl next door - until she drained her boyfriend to death in their first sexual encounter. Now she has hit the road alone and afraid. She discovers she is one of the Fae, creatures of legend and folklore, who pass as humans while feeding off them secretly and in different ways, as they have for millennia. Relieved yet horrified to find out that she is not alone, Bo decides to take the middle path between the humans and the Fae while embarking on a personal mission to unlock the secrets of her origin. With the help of her human sidekick, Kenzi (Ksenia Solo), and Dyson (Kris Holden-Ried), a sexy Fae working as a human police detective, Bo takes on the challenge of helping Faes or human clients who comes to her to solve a mystery, or to right a wrong. As the series progresses, Bo finds herself in a love triangle with Dyson and the beautiful human scientist, Lauren (Zoie Palmer) who works for the Fae.