Based on the adventures of Jack Sheppard, the thief and jail-breaker who became a folk hero in 1720s London. Jack is working as an apprentice to a locksmith when his brother Tom is sentenced to be hanged for theft. To save Tom (who has a wife and children) he goes for help to the brutal 'Thief-taker General' Jonathan Wild. Wild mediates between the government and the criminal underworld, fencing stolen goods and delivering thieves who don't pay him tribute over to the authorities. He assigns Jack a robbery in return for saving Tom from the gallows, but when Jack learns that Tom is instead to be 'transported' to the colonies for a life of hard labour he refuses to cut Wild in on the proceeds. An angry Wild has Jack thrown in Newgate prison, from which he escapes, forming his own criminal outfit with another of Wild's disgruntled associates, Joseph 'Blueskin' Blake. Determined to crush this affront to his authority, Wild uses Jack's mistress Bess to trap him and has him jailed again. By this time Jack's exploits have made him the talk of London, and one of his old victims, Lady Darlington, sends him an invitation in Newgate to attend one of her balls. A second jailbreak gains Jack legendary status, and he and Bess escape Wild's clutches by fleeing to the countryside. Bess wants them to leave for America and a new life, but when Jack hears that King George has bet the Lord Chancellor that Jack could steal the chain of office from his neck, he is tempted back to London for one last spectacular robbery.