Simon and Flora Beaufort have three perfect children and a comfortable, happy life in London. When Flora takes the children for a month-long vacation in France, Simon stays home to work on his latest film project...what could go wrong?

A Pure Clear Light examines a marriage at the moment it goes haplessly off-track: Simon succumbs to the temptation of his cool, blonde accountant and Flora heeds the cry of her reawakened faith. Ultimately, though, neither Simon nor Flora can escape the revelation that lies beyond excuses and remorse and candour, at the heart of the phenomenon called love. In St John's hands, what is commonplace is transformed and transcendent.