Jo de Vries (Googie Withers) takes the crew in the back on a van to a Dutch port (Kings Lynn). Jo smuggles them into a warehouse where they remain until the next British air-raid. She then arranges for a row boat to enable the men to get out of the harbour. Initially all goes well until they reach the bridge. Having let the fishing boats past they continue on only to be spotted by a German patrol who open fire. Sir George Corbett (Godfrey Tearle) is shot unbeknownst to the rest of the crew.

Opening scenes see an operational station in a vast expanse of flat landscape with a lone plane landing following an operation. B for Bertie is yet to return and no-one knows the plane's whereabouts. The story then shifts to 15 hours earlier when John Glyn Haggard, the pilot (Hugh Burden), prepares his plane and crew for takeoff. They are about to embark on an op or operation to Stuttgart. Having completed their mission the crew bail out over The Netherlands and are discovered and subsequently questioned by local villages who finally agreed to help them (these scenes may have been shot on location in the Fens). A key scene that may also have been filmed in The Fens given the vast open expanses of re-claimed arable landscape features the town's folk lead by Els Meertens (Pamela Brown) cycling through the countryside to the local church with the disguised British airmen amongst them. They do however have a nerve racking moment and have to pull over to allow a German patrol to pass. Closing scenes see members of the crew reunited on the airfield some three months later admiring their new plane, or Kite, and embarking on their next operation or op to Berlin.