Stories / His Last Bow · 1908
The Adventure of the Bruce-Partington Plans
A junior clerk lies dead by the Underground with submarine plans in his pocket; points, not platforms, tell Holmes the body rode the roof of a train.
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⚠️ Spoilers below. The analysis discusses the solution, including who did it and how it's found out.
Summary & analysis
Mycroft himself walks to Baker Street — an event like a planet leaving its orbit — because submarine plans of national importance are missing and a junior clerk, Cadogan West, lies dead beside the Underground with seven of the ten stolen papers in his pocket.
The body has no ticket and little blood; Holmes fixes on the points where Underground lines cross and trains sway, deducing the corpse rode the roof and fell where the carriage lurched. That places the murder at a window overlooking the tracks — the home of a foreign agent named Oberstein.
West followed a traitor who dropped the plans onto a train roof; the traitor killed him and staged the fall. Holmes baits Oberstein through the agony columns and traps him, recovering the three critical drawings. Rooftop physics turned a scattered body into an address.
Deeper reading
A body that rode the roof
The Bruce-Partington Plans features one of the canon\'s most ingenious reconstructions: a dead man found by the Underground line with no ticket and little blood, explained by the deduction that the body lay on the roof of a train and fell where the points jolted it. Doyle turns the new technology of the Metropolitan Railway into the engine of the puzzle.
Mycroft moves
The story is notable for rousing Mycroft Holmes from the Diogenes Club — proof that the matter touches national security at the highest level — and for its wartime-adjacent anxiety about stolen naval secrets. It is among the strongest of the later cases, tightly plotted where the Last Bow stories often sprawl.
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Techniques on display
Deduction & inference
Chaining evidence into conclusions on a living board.
In this story: No ticket, little blood, and a body by the rails: Holmes infers the man was never a passenger but lay on a carriage roof, dropping where the points make trains rock — a place, not a station.
Elimination
Striking out the impossible until the truth remains.
In this story: The seven papers kept and three taken eliminate simple theft: only the three that matter to a rival navy are gone, which names the buyer and the traitor's purpose.
Chronology
Laying events end to end until contradictions die.
In this story: Train schedules and the swaying-point locations are matched to fix where and when the body left the roof, converting a railway map into a clock.
Practise what this story preaches: every technique above links to a tool or game built on the same method. The best way to learn the canon is to reason along with it.