No Offence - Season 1 Episode 1

Single mother Dinah Kowalska, an off duty detective constable, pursues a murder suspect through the streets of Manchester, only for him to get knocked down and killed by a bus. As a result DI Viv Deering, her outspoken superior, instructs her to withdraw her application for sergeant, the promotion going instead to her nervous colleague Joy Freers. On a visit to the morgue Dinah sees the corpse of a Downs Syndrome sufferer, the second girl with that condition to be hauled out of a river in recent weeks, and suspects a serial killer is at large. Cathy Calvert, who appears to have the syndrome, following hospital surgery, is missing and Dinah persuades Viv to over-rule superintendent McClaren in no uncertain terms and start a search for her. Cathy is located and Dinah saves her but the killer escapes and Cathy is unable to identify him. With Cathy's family under arrest on drug charges Dinah suggests that she moves in with her.