Charlie had a powerful weapon, which he called the Lightning. When he met the Fifth Doctor, the Doctor was the first person who wasn't affected by the Lightning and could actually control it. Charlie told the Doctor he had found some material that had electric properties. He made it into a glove and used it as a weapon. Knowing that he couldn't control the Doctor through fear, Charlie proposed a deal with him.
The Doctor, with his own purpose unknown to Charlie, agreed to work with Charlie. The Doctor planned robberies for Charlie and his men to commit. Eventually, the Doctor led Charlie to a warehouse belonging to Mickey Green. In the warehouse was a cabinet. The cabinet was actually the spaceship for the aliens that were part of the Lightning. The Doctor freed the aliens and alerted the police to Charlie's whereabouts, having provided the police with proof of Charlie's previous thefts. (PROSE: The Gangster's Story)