Dr. Bendor Grosvenor and Jacky Klein seek out the work of some of the biggest names in art, lying hidden in local museums and country houses all across Britain. Britain's publicly owned art collection contains over 210,000 paintings. But at any one time, over 80% of these are locked away in storage. Among this secret treasure trove of mystery paintings are some of the finest works of art the public owns - but didn't know they had. There might even be some priceless Old Masters lost in the vaults.