Isobel suggests using Downton as a place of convalescence following a distressing incident at the village hospital. Shell-shocked new valet Lang arrives as William gets his call-up papers, and Carson strives to keep standards high, but suffers a panic attack in front of the family. Lady Rosamund is eager to unearth Lavinia and Carlisle's secret after overhearing them arguing, and romance blossoms for both Edith and Mary.