Watching Sir Iain McKellen play the ageing Holmes in the film of the same name, I was struck by the vulnerability age can bring, and how it is similar in some respects to the vulnerability of youth.
In the film Holmes befriends Roger, the young son of his housekeeper, as they look after the bees together. Holmes is losing his memory, which is deeply frustrating for someone famed for his ability to connect facts and make logical deductions from scant details. Roger does not remember his father, who was killed in the first world war, so their shared loss gives them a fresh connection. Roger is bright and insightful, and he helps Holmes to make sense of the final case he worked on thirty years previously, piecing together the facts and gradually solving the puzzle.