Somewhere in the immense landscape of northern Canada, a wolf has spent days searching for food. Their prey is seasonal and it's very hard to find.
Just as things are looking bleak for the hungry animal, it picks up the trail of migrating caribou. The hunt is on, but the job of reaching the tasty target is still a tricky one for the wolf - the caribou can cover 30 miles per day.
Watch to see if the wolf manages to catch its prey and get the meal it so badly needs.
From BBC Earth's Planet Earth: Great Plains programme.