British Expeditionary Force soldier Corporal "Tubby" Binns and his squad are left behind during the German advance through France. Facing escalating danger, they realize retreat is their only hope of survival and make their way to Dunkirk. Meanwhile, back in Britain, journalist Charles Foreman and his friend, civilian boat owner John Holden, become involved in the evacuation efforts. While Foreman reports on the crisis, Holden wrestles with the decision to risk everything and sail into the warzone.

As Binns and his men navigate the chaos on the beaches, they encounter various challenges and witness the dire situation firsthand. Concurrently, Holden overcomes his inner turmoil and joins the armada of small vessels headed to Dunkirk to rescue the stranded soldiers. The narrative intertwines their efforts, revealing the collective struggle and heroism of soldiers and civilians alike as their fates converge amid the desperate evacuation efforts.