The Chinese custom for bridesmaids, or "sisters", is to playfully impede the groom's progress as he comes to fetch his bride on the wedding day. Things take on an unexpected turn when a cheeky relative at the wedding volunteers to take on the role of a bridesmaid.

A desperate expectant father agrees to serve as a human vessel in a forbidden Taoist ritual, only to unleash a force from the underworld that drives him to reunite with his estranged mother — a Taoist medium — to confront a rogue priest before the curse consumes them both.