The coastline of Wales is imbued with Celtic myth and mystery. The animals that live here are perfectly adapted to this rapidly changing and dramatic environment where the land and the ocean meet. We follow Atlantic grey seals through the year, from courtship, to pregnancy and birth. Will a curious snowy-white seal pup make it safely through to adulthood?

The world of the shallow seas is one of the richest and most productive on earth, with an array of diverse wildlife habitats populated by a myriad of bizarre characters, seemingly straight from the pages of Welsh mythology.

The deep ocean that sits between the coast of Wales and Ireland acts as a marine super-highway for some of the greatest animals on earth. This is a journey into an unknown territory, that few people ever get to see.

This final episode in the series looks at some of the biggest challenges and issues facing the marine environment in Wales and the rest of the world today. We meet the conservation heroes from across Wales, each doing their bit in many ways, to help marine conservation and promote the importance of the ocean.