At Dunkirk during World War Two, the unlikely paths of Eve Lacy and Isobel Bloomfield cross.
Eve has been nursing injured soldiers on the front line having escaped from the bitter life her aunt planned for her back at the family farm.
Isobel arrives as part of the voluntary aid detachment to assist in the evacuations. A London debutante, the daughter of a wealthy man who has fuelled her childhood desire to fly, Isobel is biding time until she is accepted for the Air Transport Auxillary.
A shared birthday provides the basis of a friendship which continues when they arrive in back in England.
Some time after the women are posted to Park Pruett Hospital, Isobel’s dream comes true.
The women go their separate ways but only after they encounter Jack Wallace, an ace fighter pilot, who connects them by a fragile but invisible thread. Will this be a test of their loyalty?