The smell of smoke and Lost River is enveloped in an eerie haze. Newcomer to the town, Lill, is anxious. Her husband Perry is at work and she is out alone on their 25-hectare once weekender.
Gossip is spreading like wildfire through town about the fire brigade officer Eris Parsons shooting his dog. Eris and his wife Luisa aren't around to set the record straight, they've gone into hiding.
Lill is doing her best to avoid her relationship problems. She abandons her home for the day, seeking a bit of light relief with the Lost River firies.
In the midst of the Lost River Christmas carols, Backa gets a call. Section 44 has been declared in Shoalhaven and Backa is asked to join a strike team to help fight the fires.
Joey decides to give it one more go with Fifi. Lill is all passion and trouble is on the horizon when a big development is planned that will change the face of Lost River forever.
The firies become involved with an elderly couple making a nostalgic trip back to Lost River. Their life story resonates particularly with Backa and Lill.
Hank Sharp has returned from Sydney, only this time he's not alone. With him are two dodgy looking 'mates' who are seen around town acting very suspiciously.
Fifi has a new job at the Fire Control Centre and Joey is already doing the math, working out what sort of property they could buy with the extra money.
Backa dusts off his suit for a lunch meeting with the golf course developers. What Backa doesn't know is that they need 40ha of Uncle Jeff's property for their prospective resort.
Peg Beecher is back and after escaping from her nursing home, she makes a beeline for her house only to find it's been rented out to the new doctor and his family.
For Svettie, the little Russian housewife come drug dealer, life is about to take a drastic turn. An old business acquaintance, Kim Porter, turns up and convinces Svettie to invest in an aquaculture development.
In the final hour of Fireflies, days have passed since the fires. Everyone is trying to return to normal and clean up the damage, but it's not going to be easy.