Heathen (Heathen #3)

Things haven't quite gone as Aydis planned. She's been kidnapped. By the goddess Freya. And she's trapped in the impenetrable stronghold of the Valkyries. Escape seems impossible. It's hard enough just resisting Freya's spell. Roles now reversed, Brynhild plans a rescue, with help from Saga and a very old friend.