This time on Watercolour Challenge, Fern invites four daring amateur watercolourists to tackle a grand architectural pleasure pavilion set in the grounds of Castle Howard in Yorkshire. The Temple of the Four Winds, designed by English architectural giant John Vanbrugh, sits at the base of the Howardian Hills at the end of a tree-lined promenade and was used by the nobility as a place of relaxation, refreshment and contemplation. But will this Baroque masterpiece have the same effect on the four brave painters? With challenges including perspective and light, judging the finished paintings is North York Moors artist-in-residence and army veteran-turned-painter Ady Wright. He gives some top tips, including how to balance the warm and cool colours when painting in nature. While the painters work, we meet Castle Howard's head curator Dr Chris Ridgway, who has looked after the estate's listed buildings for over 30 years. We also hear how Britain's greatest living artist and Yorkshire native David Hockney was inspired by the Yorkshire countryside to create some of his greatest works in watercolour. He's quite an act to follow… will the artists stay the course?