The annual Halloween block party is the pinnacle of the year on idyllic suburban cul-de-sac Ivy Woods Drive. An influential group of neighborhood moms--known as the Ivy Five--plans the event for months. Except the Ivy Five has been four for a long time. When a new mother moves to town, eager to fit in, the moms see it as an opportunity to make the group whole again. This year's block party should be the best yet... until the women start receiving anonymous messages threatening to expose the quiet neighborhood's dark past--and the lengths they've gone to hide it. As secrets seep out and the threats intensify, the Ivy Five must sort the loyal from the disloyal, the good from the bad. They'll do anything to protect their families. But when a twisted plot is revealed, with dangerous consequences, their steady foundation begins to crumble, leaving only one certainty: after this year's block party, Ivy Woods Drive will never be the same.