Helena Vesey goes fully unhinged.
Her son Kit is in a coma and she learns of Angela's betrayal. She has been seeing Helena's ex husband and his brood.
Worse, Angela did not look after Kit properly. Telling him to get an aspirin went he was complaining of headaches.
Helena plans revenge. Poison Alex's twins with some special biscuits she has made.
During the course of her fiendish scheme. Helena is shocked to discover that Kit has always been in touch with his father.
A tour de force from Diana Rigg. It was always obvious that Helena was mentally ill but there was a predatory playfulness about her.
In this episode Helena's description of Alex's American wife and his children is shocking.