In April 1917, Matthew, who is now a Captain, returns home temporarily for a recruitment drive and Carson tells Mary that if she loves him she should let him known before it is too late. Mary’s new acquaintance, media mogul Sir Richard Carlisle causes a stir of his own at Downton however, when Rosamund and Violet overhear him arguing with Matthew’s fiancee Lavinia and Rosamund becomes determined to discover how they know each other.
With Bates out of the way, Anna becomes the object of Molesley’s attentions, while Mrs Patmore receives devastating news about her nephew. Elsewhere new valet and war veteran Lang has been brought in to replace Bates while O’Brien does her best to get her fellow schemer Thomas a job back at Downton as he returns from the front following his self-inflicted injury. Thomas soon begins work at the local hospital and develops an ultimately tragic bond with a young Lieutenant suffering from gas blindness.
Sybil also settles into her work at the hospital, but Edith’s eagerness to contribute to the war effort is thwarted when she offers to help an estate tenant tend the land, but she is quickly disappointed.