Seven celebrities of differing faiths and beliefs set out in search of St Columba, an Irish monk born 1,500 years ago who helped spread Christianity from Ireland to Scotland.
Life on the pilgrimage gets tough as the celebrities are challenged both physically and spiritually, struggling with lack of sleep and difficult questions about faith.
With the end of their pilgrimage looming, the celebrities get a taste of monastic life in a medieval abbey, but will it help them discover more about the pathway to faith?
