This play (originally broadcast as one of the Play For Today series) concerned the story of a group of Liverpudlian tarmac layers (slang: the 'black stuff' of the title meaning 'tarmacadam'). The group are assigned a job laying tarmac on a housing development in Middlesbrough, with their hotel and meals being paid for. However, ambition and greed drives four of the six men to doing a 'foreigner': a job 'on the sly' behind their supervisor's back, laying fresh tarmac for a farmer. However, this turns out to be a catastrophic disaster, after their life's savings are drained on it but end up being swindled by two Irish gypsies. The mental anguish of the four is seen, but they and the others from the collective group are sacked by the project manager. (thetvdb.com)