When German bombs set London ablaze, BBC radio correspondent Hugh Collingwood reports on the Blitz, eager to boost morale while walking the fine line between truth and censorship. But the Germans are not the only ones Londoners have to fear as a series of murders flame up amid the ashes. The deaths hit close to home for Hugh, and Aleida needs his help to locate her missing son. As they work together, they grow closer and closer, both to each other and the answers they seek. But with bombs falling and continued killings, they may be running out of time.

Never pretty enough to please her gorgeous mother, Allie will do anything to gain her approval - even marry a man she doesn't love. Lt. Walter Novak - fearless in the cockpit but hopeless with women - takes his last furlough at home in California before being shipped overseas. Walt and Allie meet at a wedding and their love of music draws them together, prompting them to begin a correspondence that will change their lives. As letters fly between Walt's muddy bomber base in England and Allie's mansion in an orange grove, their friendship binds them together. 

In 1944, American naval officer Lt. Wyatt Paxton arrives in London to prepare for the Allied invasion of France. He works closely with Dorothy Fairfax, a "Wren" in the Women's Royal Naval Service. Dorothy pieces together reconnaissance photographs with thousands of holiday snapshots of France - including those of her own family's summer home - in order to create accurate maps of Normandy. Maps that Wyatt will turn into naval bombardment plans. As the two spend concentrated time together in the pressure cooker of war, their deepening friendship threatens to turn to love.

Lt. Mellie Blake is looking forward to beginning her training as a flight nurse. She is not looking forward to writing a letter to a man she’s never met - even if it is anonymous and part of a morale-building program. Lt. Tom MacGilliver, an officer stationed in North Africa, welcomes the idea of an anonymous correspondence - he’s been trying to escape his infamous name for years. As their letters crisscross the Atlantic, Tom and Mellie develop a unique friendship despite not knowing the other’s true identity. When both are transferred to Algeria, the two are poised to meet face-to-face for the first time.

Three years into the Great War, England's greatest asset is their intelligence network - field agents risking their lives to gather information, and codebreakers able to crack every German telegram. Margot De Wilde thrives in the environment of the secretive Room 40, where she spends her days deciphering intercepted messages. But when her world is turned upside down by an unexpected loss, for the first time in her life numbers aren't enough.