As the Ellinghams prepare to leave for London, Ruth admits to Martin that she's been writing a paper on his blood phobia, and she thinks he's been misdiagnosed. Ruth is also counseling Mrs. Tishell on how to overcome her obsession with the Doc, while Penhale anxiously arranges their goodbye party. But when Chicken the dog escapes, Martin has a life-threatening accident trying to catch him. Guest starring Rupert Graves (Sherlock).