Nine-year-old Anna has moved to a new town at the edge of an Icelandic lava field. Anna's mother sends her out to make new friends but the children in the playground are unwelcoming, except for one boy, Búi. He talks Anna into doing something daring, to show the other children what she's made of. His plan works and the children are impressed by Anna. But who is Búi, and why won’t he show Anna where he lives, deep in the lava field? A young girl faces her fears and is rewarded by recognition from her peers and the friendship of a mysterious boy.