Starring Ian McKellen. Rated G.

When we meet a 93-year-old Sherlock Holmes, played by Ian McKellen with great delight, and in considerable aging makeup, the great detective is attempting to put his affairs in order. “Death, mourning, and grief are commonplace,” he states dismissively. “Logic is rare.”

Based by screenwriter Jeffrey Hatcher on Mitch Cullin’s 2005 novel, A Slight Trick of the Mind, the engrossing Mr. Holmes examines what happens when the world’s most famous sleuth, retired to the Sussex countryside and in the throes of what we used to call senility, begins reexamining his priorities.

It’s 1947 and he’s tending bees while putting his pen to paper for the first time—Dr. Watson being since departed—to get memories down while still possible, and to set some of his own stories right. This is not as elementary as it looks. For a man who “never had much use for imagination”, it’s disorienting to find that a little fiction helps paper over things that are ultimately unknowable, and goes some distance toward making life easier for other people.

This development is tested by Holmes’s frosty relationship with housekeeper Mrs. Munro (a convincing Laura Linney) and her young son, Roger (Milo Parker). Holmes softens after witnessing the lad’s thirst for knowledge and his talent with the bees. Both things baffle the semiliterate Munro, widowed in the war.

The detective is just back from Japan, where he was researching botanical help for his mental condition, and the film is framed by scenes of that journey and of a prewar case he’s struggling to recall in more detail. This structure is cumbersome, and the flashbacks are not always as engaging as are the Sussex scenes with Roger, who seems ready to challenge class norms, and to question Holmes’s authority. Still, it’s all handled with wit and surprising depth by American director Bill Condon, who has long alternated between provocative art pieces like Kinsey and Gods and Monsters and over-the-top entertainment such as Dreamgirls and the Twilight movies.

The tale is a superbly written audience charmer that’s afraid of neither facts nor feelings.