A couple's troubled relationship boils over among a dinner party at their new neighbors and their dark secrets.

A catchy tune begins a series of strange events. Before meeting up with their friends for a weekly catch-up, Cerin discovers a compelling new song. They share it with their friends Trent, Helena, Justine and Lee in turn, who all agree that it's amazing. But this "earworm" draws them into something far more deadly than they could've imagined.