The Sleepover is a gripping thriller set in the seemingly idyllic suburb of Meadow Creek. The story begins with Sarah Jenkins preparing for her son Danny's sleepover, while across town, the Patterson family faces a brutal attack, leaving the parents dead and their daughter Emily missing. Detective Laura Thompson and her partner, Mark Stevens, are assigned to the case, discovering no signs of forced entry and a deactivated alarm system, suggesting the attacker was familiar with the family.

As the investigation unfolds, similar incidents occur in Meadow Creek, with families hosting sleepovers only to be attacked, parents killed, and children abducted. The detectives notice a pattern involving the Meadow Creek Parents' WhatsApp group, where details about sleepovers are shared. They trace anonymous messages and burner phones, leading them to an exc-convict. Despite having the suspect in custody, the attacks continue, revealing a larger criminal network.