The young submariner is determined to pursue an honourable outcome. Terrified that the Allied forces won't be in time to intercept this enemy submarine, Claire and Enid enlist some unexpected (and nefarious) help and make for Moreton Bay.

The girls of Barracks 6 close in on the submarine hiding in - or off Moreton Bay … there's a mystery to its movements though and these young signallers become convinced of an imminent attack - though no-one else seems concerned.

Claire is hot on the trail of both her Australian feller, and her 'new boy' submarine… and we learn the story of this young Japanese submariner - his famous brother and his grieving mother.

Claire, Enid, Stella and Annie lie to their friends and family. They're signals operators in the Australian Women's Army Service – but not regular 'sparks'. These girls work for General Douglas MacArthur's Central Bureau – the Inter-Aliied, Ultra secret Intelligence Organisation.