A local MP is murdered by a far-right extremist gang in Snowdonia. DI Ruth Hunter and DS Nick Evans arrest one of the killers, Raymond Clarke, who agrees to give evidence if he and his family are taken into protective custody. Ruth is sure they'll be out of harm's way in the remote wilds near Bala Lake.

But the location of the safe house is leaked and Clarke's family is kidnapped. Ruth and her team must pursue the gang across North Wales and work out where the leak came from before it's too late.