No one is immune to the allure of that cruel and merciless mistress: time.
She saps strength and suppleness from athletic bodies, defies every cream to wither beauty and dulls the sharpest intellects.
Mr Holmes imagines the twilight years of one of literature’s icons, who is facing the grim reality of dementia with what remains of his once-glorious wit, aided by doses of a rare restorative plant from Japan called Prickly Ash.
This Sherlock, portrayed with dignity and steely resolve by Sir Ian McKellen, is no longer the aloof master of deduction who traversed the pages of Sir Arthur Conan Doyle’s imagination.
Instead, he tends bees on the Sussex coast, haunted by the one case he failed to solve - if only he could recall the facts.
Bill Condon’s slow-burning drama tests our little grey cells with a perplexing subplot: The Curious Case Of The Thrice Oscar-Nominated Actress And The Wayward Accent.
Laura Linney is one of the finest performers of her generation, but here she is undone by a vocal delivery that roams wildly between the West Country, Ireland and America.
Back to the plot. The year is 1947 and Sherlock Holmes (McKellen), now 93, is a shadow of the brilliant logician.
The ageing sleuth has retired to Cuckmere Haven, where he fusses over his hives, struggles to piece together fractured memories and infuriates his widowed housekeeper, Mrs Munro (Linney).
Her spirited son Roger (Milo Parker) is fascinated by Sherlock and the boy shows a natural aptitude with the bees.
The lad inspires Sherlock to delve into the fog of the past to recall his only unsolved case - a missing person enquiry in 1919 involving a distraught husband, Thomas Kelmot (Patrick Kennedy), and his beautiful wife Ann (Hattie Morahan).
As Sherlock’s addled mind drifts between that ill-fated pre-war investigation and the present, the old man edges ever closer to an inglorious end.
Mr Holmes is distinguished by McKellen’s measured central performance and the strong support from rising star Parker.
The script slowly unravels the myth of the literary sleuth, including one bittersweet scene of the ageing Sherlock watching a film in which Basil Rathbone portrays him with unnatural gusto.
We’ll meet Holmes again, in many different guises, but few will be as heartbreakingly frail or haunting as this.