Sub Zero - Episode 6.
The Doctor's radio message comes too late, and the Daleks decimate the city of Sydney with a polaris missile... they don't waste any time subjugating the survivors in typical Dalek fashion, which to the uninitiated involves rounding up refugees, taking them as slaves to do their evil bidding and exterminating any that attempt to escape. It is soon revealed that survivors are being put to work in a makeshift Dalek factory, using genetic material from humans to create a new race of Daleks (Parting of the Ways, anyone?)
Meanwhile, the Doctor wastes no time in appealing to the Australian authorities, currently gathered in Melbourne, that using conventional weapons against the Daleks will fail and that the best option is to let him and Lt. Davis penetrate the Dalek's camp in order to discover exactly what they're up to. The Australian government reluctantly agree and our two heroes sneak into the ruined city under the cover of darkness in a battered pick up truck, however they are soon surrounded by a gang of Dalek slaves and ordered to get out of the vehicle. At that moment, one of the slaves moves towards Lt. Davis with a sinister looking device...