While on a mission to rescue two servicemen captured by the Viet Cong, "Captain Norman Hopper" (John Saxon) is bitten by one of these men when he attempts to pull him from the pit. Afterward both of the men are committed to a psychiatric hospital while Captain Hopper is allowed to return to civilian life. Unfortunately, it doesn't end there as one of the men named "Charlie Bukowski" (Giovanni Lombardo Radice) is temporarily released and not long afterward suddenly goes berserk which results in the deaths of at least two people. Then upon being returned to the psychiatric hospital he and the other serviceman by the name of "Tom Thompson" (Tony King) manage to escape along with a nurse named "Helen" (May Heatherly) who was bitten by one of them and shares the same craving for human flesh as they do. Now rather than reveal any more of this movie and risk spoiling it for those who haven't seen it I will just say that this turned out to be a fairly decent type of "zombie film" even though it didn't necessarily fit the technical parameters for that particular sub-genre. The acting was decent and the plot moved along quite well. In any case, for what it's worth I liked the movie and I have rated it accordingly. Slightly above average.