Iolo Williams explores Singleton Park in Swansea in the first of a new four-part series of Iolo's Great Welsh Parks. Iolo discovers the wilder side of this urban park when he tries to track down foxes and an elusive parakeet, carries out an experiment on a pair of nest-building long-tailed tits, investigates what the local peregrine has been eating and finds out about the many different types of insects living in the colourful botanical gardens.

Wepre Park is nestled amongst the urban sprawl alongside the Dee estuary in North East Wales. Seeking out the park's wilder side, Iolo Williams tracks down badgers, heads out with wardens as they survey for rare great crested newts, comes within centimetres of a wood mouse and finds a scary-looking giant wood wasp amongst a log pile. It's an important park for the people to enjoy the outdoors, with areas of ancient forest, brooks, ponds and open spaces.

Iolo Williams finds amazing wildlife in a once-abandoned old industrial site turned urban park on the coast of Anglesey. Holyhead Breakwater Country Park is now a pleasant escape for people and a place where he discovers sparrowhawks, little owls and the charismatic chough. He has a magical encounter with a weasel and gets up close to grasshoppers. In late autumn, filming coincides with the tail end of Hurricane Gonzalo, giving a chance to see the grey seals frolicking in wild seas.

Iolo Williams visits his final park of the series and finds himself in the old industrial town of Pontypool in south-east Wales. The park here was given to the community for leisure by the Hanburys, a family of industrialists. It also happens to be home to thousands of nesting bees and the very rare native crayfish. Iolo learns how to identify the sex of maybugs, and discovers that deer have been known to use the park and that otters live in the river.