Coronation Day, 1953.
In the Somerset village of Sawbridge, young shopkeeper Molly Heywood slips away from the celebrations to her friend's cottage and makes a shocking discovery: Cassie is dead and her six-year-old daughter Petal has vanished without a trace . . .

In her grief, Molly seeks help from her childhood friend George, now the village policeman, but no one can find Petal. The only clue is a letter from London, where Cassie once lived. Despite George's reluctance and her growing feelings for him, Molly resolves to go to London in the hope of discovering the missing child.

Arriving in the big city, Molly quickly learns it's a dangerous place for a country girl on her own. But there's hope too - in the Blitz-ruined East End, she unexpectedly finds friendship with strangers from Cassie's past and, with handsome, mysterious workman Charley, the possibility of something more.

However, the closer Molly gets to the truth, the more perilous her journey becomes. She has given up everything - her home, happiness and a chance at love - all to find Petal. But is she also risking her life?