Harry Slinger was a mate of Don Brennan's. Don was Harry's taxi driver of choice to transport him and his greyhound Lucky to the dog track, where Lucky competed. In May 1989, after Lucky crashed out of a race in St. Helens, Harry couldn't pay Don the £40 cab fare and asked him to wait outside a pub while he went inside to borrow the money. For security, Don insisted that Lucky stay in the car with him - a condition which offended Harry, who blamed the dog for his current predicament, threatening to tell a Doberman Pinscher that she didn't like Germans.
After failing to procure the £40, Harry persuaded Don to take the dog in lieu of payment. He later turned up at 5 Coronation Street with the the money, firstly encountering an irate Ivy Brennan who was upset over a chewed sofa cushion. Harry was about to leave when Don returned from walking Lucky, and shocked both Harry and Ivy by announcing that he'd decided to keep the dog and race her himself. Harry swore to fight for Lucky, but he never bothered Don or Ivy again.
Three weeks later, Don and Ivy discovered that Lucky was heavily pregnant. In July, news that she had given birth to five pups reached Harry, who informed his friend Mickey Lee as his canine had sired the pups. Harry and Mickey had a deal that half the pups would go to Mickey, a deal which Mickey considered still binding. Harry agreed to explain the situation to Don and tell him to expect Mickey to call, but he failed to do so and when Mickey arrived at No.5 to claim the pups, he had to explain the situation himself.