Xena: Warrior Princess - Season 6 Episode 7

A Norse man called Beowulf shows Xena a strange padlock which reminds her of her past in the Norselands. The next morning, Xena's gone: she's travelling with Beowulf to mend some actions from her past, and Gabrielle decides to follow them. She finally reaches the Norselands, where she meets a woman called Brunnhilda who tells her about Xena's past as an evil valkyrie and her relationship with Odin, and how he told her where the powerful Rheingold was kept.