Paul and Bob go lake fishing in Wiltshire, and they are up before sunrise to give themselves a fighting chance of catching a crucian carp - one of the UK's most shy and elusive species that prefer the shadows of dawn and dusk and are notoriously tricky to catch. A relative of the goldfish, they have been likened to trying to catch a unicorn. Paul and Bob will need to employ every ounce of stealth they can muster, but will it be enough to net a crucian?