The Chord (Episode 1 Season 3‪)‬

Leaving behind the intrigues of the Organization, Ella and Finn cross into Aelfheim. Finn's plan is to throw the Dark Elves off his trail and investigate whether his mother is still alive. Unwilling to stay behind, Ella follows, determined to stay by his side, no matter what.
It's a world plunged into an ice age, a frigid, lethal landscape full of nightmarish creatures — not to mention the elves — all of it a shock to Ella.
In Aelfheim, she is the outsider. Traveling with Finn who's been ostracized by his people makes matters worse. As they venture deeper into elf country, Ella fears her presence will only complicate things for Finn.

Then again, in Ella's book, there's only one way to find out...