Cause For Concern is the 655th episode of The Bill
P.C.s Loxton and Quinnan are talking when a speeding driver goes past. The driver advises that she is on her way to hospital, where her husband is in a critical condition. Loxton and Quinnan are sent to check out the woman's address and surprise two burglars. P.C. Stamp is moving the burglars' van when one of them gets on board.
P.C. Stamp and W.P.C. Datta are called to check a domestic disturbance. The husband is very domineering, and Datta is concerned about the wife. A fresh argument breaks out and, on entering the house, the officers find the husband stabbed and his wife in shock with a knife in her hand. She claims it was an accident.
D.S. Pearce is at the hospital checking on the victim when he overhears a woman asking about her husband who is supposed to be injured at the hospital. D.C. Woods talks to friends of the couple and their description of the wife's behaviour doesn't tally with the woman Woods and Pearce have spoken to, and who turns out to be the sister.