Brass faced many difficulties in Italy due to lawsuits concerning the production of Caligula, so he filmed Action in London in 1979.

Bruno Martel (Luc Merenda) is a "Z movie" actor with hero syndrome, often quarrelling with directors.

One day, during a nervous breakdown, Bruno "rescues" Doris from the set, leaving the town to encounter various absurd situations.

They meet an old anarchist (Alberto Sorrentino) who thinks he is Giuseppe Garibaldi and the three are locked at a mental asylum where Doris commits suicide.

Bruno and "Garibaldi" escape and take refuge at an awkward petrol station run by Florence (Adriana Asti) and her invalid husband Joe (Alberto Lupo).