Mr. Jabez Wilson consults Sherlock Holmes for the purpose of solving the mystery of his sudden loss of employment with the Red-Headed League.
Accordingly, Wilson is a pawnbroker at Saxe-Coburg Square in London. He has an assistant by the name of Vincent Spaulding, a man who seems to enjoy photography so much that he often sequesters himself in the cellar to develop his pictures. It is Vincent who brings an interesting advertisement to Wilson about a possible employment opportunity for red-headed men. When Vincent suggests that Wilson (who has flaming red hair) is well-suited for the position, Wilson agrees and decides to apply.
As the story goes, Wilson is hired by one Duncan Ross to copy out the Encyclopedia Britannica by hand at a pay of four pounds a week, for four hours a day. After eight weeks, Wilson is both surprised and frustrated to discover that his employment has been unceremoniously terminated without advance notification of any kind. As things stand, Wilson desperately needs Sherlock Holmes to help him find out what the Red-Headed League really stands for and why members of the League decided to play such a horrible trick on him. After all, he was starting to rely on the four pounds a week to supplement his meager income from the pawnshop.
The story concludes with Sherlock Holmes, Dr. Watson, Peter Jones (an inspector from Scotland Yard), and Mr. Merryweather (the bank director of the City and Suburban Bank) waiting in a bank vault for the notorious criminal, John Clay. Clay is none other than Vincent Spaulding, Jabez Wilson's assistant. His foray in the cellar was for the purposes of tunneling a path to the vaults of the City and Suburban bank, which abuts Wilson's pawnshop at the corner of the Square.
Jabez Wilson learns that he was hired by the Red-Headed League as a ruse to get him out of the pawnshop for a several hours a day so that Clay and his assistant could engage in their tunneling activities without benefit of observation.