Fort Worth Police Officer Megan Luz and her fiancé, firefighter Seth Rutledge, will soon be walking down the aisle--assuming they live to see their wedding day . . . WHEN A STRANGER CALLS, CHAOS ENSUES. A series of bogus reports of active shooters has rattled the Fort Worth PD. The SWAT team has been repeatedly deployed to what turn out to be nonevents. When no connection can be made between the "swatting" calls, Megan's mentor, Detective Bustamente, is at a loss. Are the phony calls being made by copycat criminals, or is there a link they haven't yet been able to identify? Megan and Brigit join the investigation. But will they be able to stop the calls before the department's reaction turns deadly? THEN THINGS GET EVEN HOTTER. If the bogus shooter calls aren't enough to keep our favorite first responders on their toes and on edge, an elusive arsonist seems intent on pushing the city's firefighters to their limits, with increasingly dangerous results. Who is setting the fires and why? The fire and police departments team up to track the sinister offender, whose offenses hit closer and closer to home. Can the felonious firebug be found before his efforts turn fatal?