Anna is a semi-successful but frustrated sculptor in a Northern city, who has grown all but estranged from her mum and brother since her dad’s death. The day before she is due to quietly leave the country for a teaching job in Denmark, her mum summons her back to the family home in a sleepy village, where she must put the welding skills she learnt from her dad to mysterious – and urgent – use.

The reluctant Anna is liberal, gay, metropolitan, creative and childless, seeing herself as everything her mum – the conservative and sometimes controlling Helen – is not. Anna’s piqued curiosity and the promise of generous payment coaxes her to go, whereupon she discovers a large metal cage, wrenched open. Her brother – the gentle, damaged Graham – has always been trouble, with a long history of addiction, but has now become, much to their mum’s embarrassment, a werewolf. Last night he escaped his cage, killing the family dog, and the poor chap at the all-night garage was torn apart. Tonight, Graham will change again. Something must be done.

Initially, Anna wants only to fix the cage and go. To walk away and leave her family to their problems. But when the local vicar – the unassuming but manipulative Father Richard – arrives to perform a dangerous ritual on Graham with the help of dubious, self-described werewolf expert Dan Halston, it reawakens in Anna’s old feelings of protectiveness toward her brother.

At the rather civilised family lunch that Anna’s Gran and Helen have prepared, Anna’s questions begin to complicate matters for Richard and Dan. As the stresses of what is about to happen to Graham come to a head, tempers fray and everyone’s true intentions are laid bare. Anna picks a side and chooses to stay. When two horrifying deaths then occur and a monstrous home invasion begins, Anna, Helen and Gran – along with Graham’s hapless mates Beano and Mickey the Twitch – must not only fight for Graham, but for their own survival.