Genocide is abhorred by civilised opinion all over the world - and protesting against it is becoming a cause taken up by many young people. Should the purpose of Western nations above all be to prevent genocide or to intervene whenever it occurs?

Screamers approaches this bleak subject via the medium of rock 'n' roll. System of a Down are a Los Angeles heavy metal band, popular throughout the world. Three of the four band members are Armenian by origin - they emigrated to LA via Iraq - and they have turned their concerts into a form of lobbying, wanting to see the 1916 Turkish massacres of Armenians recognised as genocide.

Carla Garapedian's film follow the band as they mount a campaign, and explains the background. The Turks have never recognised that the massacres happened: they still allege that the killings took place in self-defence. Defenders of the Armenian position have been murdered in Turkey.

Garapedian's film is a new way into a very topical subject.