When Brannagh’s boyfriend, Nikki, disappears on a bird count in Northern Ontario, she reluctantly returns to the east coast for a childhood reunion. Back in grade school, the all-girls club Tuatha-de-Dananns vowed to "protect one another's self-a-steam, forever and ever amen." As Brannagh struggles to solve the mystery behind Nikki’s vanishing, she begins to suspect that someone is taking the club's oath too far...even to the point of murder.