Jacob Singer is a soldier in vietnam, is knifed in the abdomen, and is suffering. To escape the suffering he periodically falls into dreams of an alternative future, and into dreams about his past. Several scenes make it apparent that he does not survive his injury in vietnam: when he goes to see "Dr Carlson" as a "vietnam vet" the receptionist says she can't find Jacob Singer in her files; at the party he goes, the woman reading his palm says his life-line shows that he is already dead.
The dreams he has while dying are affected by being on the drug "ladder" which makes the dreams more unpleasant than they might otherwise be.
Very remininiscent of "An Occurance at Owl Creek Bridge" only his death takes longer and his escapes into his dreams go on longer and are a mixed bag of bad dreams as well as good dreams.
A very moving movie about the transition from life to death and about things that can make this more unpleasant than it needs to be - like for example war, and certain drugs.