A Fae Opera singer, Ianka, shows up at the Dal and is ecstatic to see Bo again. Only problem is that Bo doesn't remember ever meeting her. The singer's Fae power allows her to use music to stimulate the mind. She can help people remember or even kill them with her sound. Ianka wants Bo to fulfill her promise. She wants help getting her freedom from her owners in exchange for helping Bo remember.
It gets complicated when not one but two of Ianka's previous owners show up to claim her. One of them threatens to blow up the Dal to get her back. Ianka helps Bo get back a few of her memories before she runs off with her lover, Marcus. It turns out that Marcus only wanted to use Ianka to kill others. Instead, she kills him with her song and then dies.
Bo struggles with the new memories and her Dark Fae status. She tries to get with Dyson, but Trick stops them and warns them it's against the rules. After Ianka's death, Bo ends up with Dyson again, but she's not acting like herself. The Una Mens show up and take Dyson into custody for being with Bo.
Kenzi and Hale kiss after he saves from from Ianka's death song. Kenzi is fine, but Hale starts to bleed from his ear.