A firebug is stalking Oak Grove and internet researcher Harmony Duprie is on the case. It starts as a simple data analysis project for Police Chief Sorenson, but things get personal when the house she renovated is targeted. The arsonist is in it for the glory, posting videos of his exploits on social media. So, Harmony calls for backup from her favorite computer hackers, Eli, Lando, and Scotty. Complications arise when Fiesker, a fire investigator with a chip on his shoulder, is brought in to unmask the culprit and put an end to the fires. Then there's the mysterious emails being sent to the town's firefighters. And who is leaving a trail of Celtic brooches behind? Harmony finally gets a break when Jake, her ex, stumbles across information that might lead to the guilty party. Can Eli, Lando and Scotty help Harmony track down the pyromaniac before someone gets hurt? Or, worse yet, killed?