The team hunts for a person who jeopardized a classified vaccine project; Deeks returns.
A ghost who knows of a hidden munitions dump with unexploded bombs confides in Melinda that one of those bombs is missing and in the wrong hands, warning that someone will lose their life.
When violence erupts at a popular food truck festival, the team must contend with a deadly cartel determined to recover a lost drug shipment at any cost.
The guys' plans for a video game tournament go south when Will, thinking he's going to sneak out and play, gives Theresa some medication recommended by Kenny to cure her insomnia.