As the story jumps back in time, 29-year-old Winton, portrayed by Johnny Flynn, is a London stockbroker traveling to Prague for a week to aid refugees. His week-long trip turns into a full-time operation because, as Winton says of the unfolding humanitarian crisis,

'I have seen this and I cannot unsee it.'

And so, with the help of his mother Barbara Wertheim Tuchman (Helena Bonham Carter) and volunteers on the ground, Winton begins the undertaking of a lifetime to evacuate children from Prague and re-home them with foster families in the U.K.

His story proves that a few months of helping others can turn into generational legacies, that 600 souls can turn into 6,000, and that one life can have a lasting impact on the world.