Heartbeat (1992) : 5x15

A father has kidnapped his son from his wife and brought him to Aidensfield. The boy becomes ill with polio, so a mass vaccination is arranged. Once the boy is taken to hospital his dad runs away, but Nick says he won't go far as he is worried about his son. It turns out that he too, has polio and he's found just in time. The boys mother arrives after having hired a private detective to find her son, but she admits she drove her husband into snatching their son. Blaketon is now president of the rugby club, and Phil is on the team. Greengrass has a go at playing talent scout, but his plan doesn't work out. Nick meets Jo the new school teacher and the fact that he's noticed her is obvious!