Coast explores the strong bonds we have with our neighbours across the North Sea in Denmark. The Danes top the polls as the happiest people on Earth and Neil Oliver wants to know what they have to smile about. He discovers how their coast keeps the Danes happy. Miranda Krestovnikoff meets some unflappable red deer, who manage to make themselves at home on a windswept shoreline despite the fact that they share the sand dunes with tanks from the Danish army. And Dick Strawbridge gets access to the construction of one of the world's largest offshore wind farms.