A breakdown that leaves her a fearful emotional block of ice.
Series two is based around the return to the village of her ex-husband with his younger wife and baby girl.
This is gripping television in that the dialogue is mostly stiff and uncomfortable with each of the few situations like her home, the medical practice, some outdoors shots in the village always edgy and laced with unease.
Which means there's no relaxing during this programme. You're constantly on edge even though you're not bombarded by conversation.
The hurt, anger and cruel mind games in every frame are palpable.
You feel yourself bracing for every barbed comment.
Jones is a superb actress - she uses her body language and expressive dark eyes to chilling effect at times.
You can feel her hurt and anger.
Husband Simon (Bertie Carvel) is constantly on about his nasty scheme to move back to Parminster and sort Gemma out.
His way this time is quietly gruelling with a serious psycho element because she had literally made him pay, when she caught him out in an affair with a younger woman.This series the paybacks are just eye watering.
In fact the wealth of lies and betrayal are legendary - you're always wondering what will happen next.
And it leaves me struggling why people today somehow condone or forgive too easily when it comes to mentally damaging, physically brutal, wretched and destructive behaviour.
This series highlights emotional trauma, which makes for addictive viewing because its sole focus seems to be mind games.
The first series was an award winner and this second series will no doubt be another award clincher because it's moving, superbly directed and at times is spookily real.
