When a young homeless man is found murdered in the playground of their local park, the Pack – a group of friends who meet regularly to walk their dogs together – leap into action, determined to get justice for him even if they have to bark up every tree in the neighbourhood. But the discovery of another body, this time by the canal, suggests the killer may only be getting started. And when one of their own is targeted, it’s clear that whoever it is has a bone to pick with the Pack.

With the trail getting closer to home, can Louise and the gang find the murderer in time, and bring them to heel?