Chloe "Donny" Donavon is a Firefighter/Paramedic who discovers an attraction to, Caitlin "Caity", a dispatcher. She has known Caity for a few years but never thought of her as anything other than a friend and fellow member of the fire department. Their relationship goes against everything Donny has believed about keeping romantic entanglements away from the workplace, especially since she works with and supervises Caity's younger sister, Pauli.
Kristi, who is Donny's mentor, supervisor, and friend at the station is behind Donny's sudden promotion - but that promotion could change her own career as well. Kristy is dealing with things from her past that she can no longer repress. How will that affect her relationships with her protégé and crew? What happens when the strongest of the strong finds out that she can't remain an island forever?
Lights and Sirens shows a crew of well meaning men and women who come together to battle fire, fight illness, injury, and death for others. Can they hold it together for one of their own?