After two years of military training in Brazil and Cuba, FRANCO CASTILLO, a member of the Chilean Revolutionary Left Movement (M.I.R.) returns to Chile in 1980 with the intention of contributing to the overthrow of the Chilean dictator General Augusto Pinochet and his military junta. He plans to build a bomb and detonate it at the Santiago Stock Exchange during a visit by the top military officers of the Chilean Secret Police.While building the bomb Franco goes to watch a football match at the National Stadium of Chile in Santiago. At the game he meets an old friend of his, DIEGO MARTINEZ, who invites him to visit him and gives him his address on a piece of paper.Franco builds the bomb but while travelling to the Stock Exchange to place the bomb, it detonates prematurely in the Santiago CBD, killing him and killing and injuring a number of civilians. During the ensuing Secret Police investigation the note with Diego Martinez's address on it is discovered in Franco's shack at the Raul Silva shanty town in Santiago. Diego is arrested as a suspected accomplice of Franco Castillo and brutally tortured by two members of the Secret Police, Captain ARMANDO CASTRO and Captain CARLOS ALVAREZ but is eventually released. Diego swears revenge on the two police officers.After establishing where the two policemen live Diego finds work as a gardener with Armando Castro and, using a stabbing instrument made from the steel tine of an old garden fork, manages to kill the policeman and his wife and escape undetected. He then finds employment as a painter at Carlos Alvarez's house. Continually thwarted by the policeman's vigilance Diego eventually gets the opportunity to kill the policeman when the electricity supply is interrupted during a violent late afternoon thunderstorm. Diego enters the house undetected but in the darkness only manages to wound the policeman. Diego's escape is stopped by the appearance of SERGIO MIRANDA whose wife was killed when Franco's bomb exploded prematurely and who comes to visit with his five-year-old daughter. Diego manages to take the child hostage but while he is planning his escape Carlos manages to recover sufficiently to sneak up behind him and kill him. "Nothing is more costly, nothing is more sterile, than vengeance." - Winston S. Churchill