This is not a Bulldog Drummond picture despite the title playing off Jack Buchanan and his previous association with the character. Here he plays the role of Test Pilot 'Bulldog' Bill Watson. His friend Derek Sinclair (Sebastian Shaw) is convinced that the new man in his love's life is collaborating with the Nazis by sabotaging an armaments plant.
On the outbreak of the Second World War, a group of six children from the East End of London are evacuated to the village of Payling Green. The boisterous pair Charlie and Ern are lodged with the local vicar and proceed to torment, mock and terrorise his sensitive and delicate son. They then get involved in petty-thieving and vandalism, before being taken under the protective wing of a local female novelist with progressive social views.
In Legok, a Japanese spokesman gives a speech regarding the formation of military units for native Indonesians. Two village boys, the best friends Saman (Sambas) and Anang (Mohamad Mochtar), try to join the army. Saman is not accepted owing to a lame leg, but Anang begins training. Saman, meanwhile, begins working indirectly for the Japanese occupation government by taking up work at a food company.