Peter van Rodijnen has travelled the world, capturing breathtaking footage of some of the most spectacular oceans but has never been drawn to what he saw as the cold, lifeless grey waters of his native North Sea. All this changes when he is sent on assignment to Denmark to film the spawning of the majestic Atlantic salmon. After an absence of more than 60 years, these great ocean icons are returning once again to European waters. This experience urges Peter to go out and learn more about the secrets of this little-known world. As Peter embarks on his journey, he faces a number of challenges. He encounters dangerous currents, poor visibility and fierce storms, but his determination to uncover the secrets of this untamed natural wonder never wavers.