Keith's a pain in the neck!

A patient with a grudge spells trouble for Sam this week! Sam's action-woman ways come back to haunt her, when a familiar face is brought into the ED.

In the traumatic aftermath of the chemical explosion earlier this year, former army medic Sam lost her cool with a patient's angry relative, Keith. When he lunged at Dylan, no-nonsense Sam restrained him in a headlock!

This week Keith (Ashes to Ashes star Marshall Lancaster) returns to casualty after an ongoing pain in his neck causes him to crash his car, while his new girlfriend, Tanya, is in the passenger seat...

While examining Keith, Zoe realises the twinges in his neck may be something more serious and orders some tests - only to discover Keith has a minor fracture in his neck!

Meanwhile, Tanya discovers she has Hepatitis C - and she may have passed it onto Keith. Believing his world is falling apart, Keith realises his neck injury was probably caused by Sam's headlock and irrationally blames her for everything that's going wrong.

When Tanya then dumps him, Keith focuses his full fury on Sam - he's determined to make her pay for ruining his life by making sure she loses her job!

Also this week, Jean Boht - best known as Ma Nellie Boswell in BBC1 sitcom, Bread - guest stars as seemingly sweet old lady, Doris.

Doris has Alzheimer's, which causes her to act in unpredictable ways. When a young lad, Thane, doing community service comes to tend to her garden, Doris is convinced he's her dead husband, Jack.

Both Thane and Doris later end up in the ED, and Doris's daughter, Sandra, believes Thane is responsible for her mum's injuries. But nurse Lloyd pieces together a very different jigsaw of events.