Summary
Jabez Wilson, a pawnbroker with a uniquely intense head of red hair, comes to Holmes to ask for help about a mysterious job he, Wilson, had been working. For the simple menial task of copying out parts of the Encyclopedia Brittanica for a few hours each day, Wilson was paid a handsome amount by a so-called Red-headed League; but suddenly the Red-headed League disappeared.
Holmes investigates and concludes that Vincent Spaulding, who had only recently begun working as an assistant at Wilson's shop and who had shown Wilson the Red-headed League's advertisement in a newspaper, is actually the infamous criminal John Clay. He deduces that Clay has been using the ruse of the Red-headed League to keep Wilson out of his shop so that in his absence he, Clay, along with some accomplices could dig a tunnel to the vault of a neighboring bank.
Along with a bank executive and a police chief, Holmes sets up an ambush in the bank vault and catches the criminals.
Analysis
The story of the Red-headed League is based on an extraordinary and somewhat implausible detail: Jabez Wilson's red hair. In effect, Conan Doyle constructs the mystery in reverse, beginning with the criminal, John Clay, who himself constructs a plot out of the detail, and then having Holmes trace back, as though reverse-engineering, the conspiracy. As he often does, Holmes reasons based on psychology, specifically by probing at different events in the client's story and pondering the possible motives of this and that actor for doing what they did; thus, Clay's eagerness to work for Wilson at half-wages points, in Holmes' analysis, to an unknown and suspicious motive. Working his way back from this identification of the suspicious character, Holmes asks of each of the aspects of Wilson's situation how it could be useful to Clay.
The scene in which Watson hides with Holmes and two other men in the pitch dark of the bank vault in ambush for the robbers is also one of the most laden with the threat of danger among all the stories. It is the scene of action, and there is one in each of the stories; but the confrontation that is expected is with a criminal known to be violent. Conan Doyle has Watson describe with vividness the individual experience of anxiety, especially with the light effects of the dark room, the emergence of Clay's light, and the flash when Holmes' uncovers his own lantern to confront the criminals; this makes for a thrilling experience for the readers.
