London, October 1940. As German bombers increase their nightly raids on the capital, the Blitz Girls must be braver than ever to protect innocent lives and keep the fight against Hitler alive.

Dot, encouraged by her friends, is finding her independence and takes a full-time role as an ARP warden. As she finds new courage in the blackouts, her past might still be lurking in the shadows...

Peggy makes it her mission to help children caught up in the bombing find safety at her parents' large house in the country. When she returns home, however, she realises her own family need her more than ever. But can she leave her friends in the line of fire?

Vivian spends every moment not behind the wheel of her ambulance at the bedside of the man she loves, helping him recover from a terrible crash while defending the British skies. When she is torn between his hospital ward and the site of the latest blast, she faces a heartbreaking choice.

As each night becomes more dangerous for the Blitz Girls, will they have the strength to help each other through and keep the light alive in the darkness?