In a riotously gory inversion of the Christmas story, an older couple plan to channel the ghost of their dead grandson into an unborn child

There’s something deliciously subversive about the backstory to this offbeat horror film, which was made in Canada. Director Justin G Dyck and screenwriter Keith Cooper have collaborated on a long list of treacly, holiday-themed, made-for-TV movies with titles such as A Very Country Christmas, Christmas With a View and A Christmas Village. Anything for Jackson, however, is a riotously gory, impish inversion of all things yuletide, in that it stars sweet-featured elderly character actors Sheila McCarthy and Julian Richings as grieving grandparents Audrey and Henry Walsh, who kidnap pregnant Shannon Becker (Konstantina Mantelos) in order to perform a satanic ritual on her. It’s as if Ruth Gordon and Sidney Blackmer, the little old couple who lived next door in Rosemary’s Baby, got to be the stars of their own movie.

Audrey and Henry’s goal is to channel the ghost of their dead grandson, Jackson, into Becker’s unborn child; but, wouldn’t you know it, deals with the devil have a way of going wrong – or having nasty consequences in the fine print, such as bringing forth demons and ghosts with murderous instincts of their own. Plus, their main adviser on matters demonological is a bitter “incel”-type (Josh Cruddas) who lives with his mother and is prone to bitching about the leadership at their satanic church, an outfit quietly run out of the local community centre where members bring home-baked goods for breaktime.