Miss Saigon is a love story and takes place first in Vietnam during the last days of the war 1975 and then three years later in Bangkok and in the USA.
In Vietnam Chris, a marine from the USA, and Kim, a girl who has to earn her living by working at a brothel, meet and fall in love with each other. A few days later Saigon, the capital of Vietnam, falls and Chris must leave the country. He fails to take Kim with him and she must stay in Vietnam.

Three years later Kim has to shoot her own cousin, a commissar, because of the vow their fathers had made which was that they would marry each other. She escapes to Bangkok with the owner of the brothel, called the Engineer, and her and Chris son Tam.

In the meantime Chris, married to Ellen for a year, finds out that he has a son. Chris, Ellen and Chris friend John, who is trying to find the American fathers to the children in Vietnam - "the dust of life", go to Bangkok to find Kim and her child.

John finds Kim, who is working as a bargirl and tells her that he is going to get Chris but the Engineer doesn't trust him and make Kim to go to Chris hotel room. When she comes there Chris and John has already left but Chris wife Ellen is waiting in the room. This is the first time Kim hears about Ellen and at ones her hopes are smashed into pieces. She tells Ellen that Chris must come to her place tonight and then leaves the room.

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