Arthur, Geoffrey and Andy first walked 177 miles of Offa's Dyke twenty years ago when they were at university together. Now meeting up in middle age they vow to walk it again come hell, high water and hypertension! As rain, rows and resentment threaten their best intentions, they are joined by a middle aged housewife desperate to escape her boring, sometimes violent husband. As the miles pass they stumble across nubile Swedish nymphets, a dead body, a battalion of squaddies, a pub full of Clint Eastwood lookalikes... and a mystery man! Will the four venturers discover themselves as they complete their marathon hike or will they end up killing each other?