I'm going to spoil this movie to spare you from ever having to watch it.
The title may lead you to believe that this is one of those enigmatic arcane Italian art movies made by Antonioni in his black-and-white period, but it is not. It's just another grade Z movie from Roger Corman. It's accolades include inclusion in the book "The Fifty Worst Films of All Time" and being roasted by MST3K. But still I was disappointed. It has a swamp and it has women, two of the key elements for any successful movie, but they just don't gel in this one. It's only saving grace, besides Beverly Garland frequently posing sideways in a tight shirt, is the rattlesnake they encounter. Unfortunately, the picture quality is so appalling that it's barely visible. It looks like an Eastern Diamond-backed Rattlesnake that somehow had its head blown off so we can watch it take its last breaths but I'm not even sure of that.
4 women escape from prison, cut off the legs of their pants into short shorts, and boat through a Louisiana swamp to recover some stolen diamonds with the guy who played Mannix in the 70's as their hostage. The redhead doublecrosses them and escapes with all the guns, the diamonds, and Mannix, who she's got the hots for, but instead of killing the other women as they sleep, which any sane psychopath would have done, she decides to climb a tree and wait for them to come after her so then she can shoot them, leaving Mannix tied to a tree below, vulnerable to all passing rattlesnakes. As chance would have it, a rattlesnake does happen on the scene and it immediately takes a dislike to Mannix, striking at him a few times from about 10 yards away. But the redhead, now mortally wounded by a spear thrown in her gut, shoots the snake to save Mannix before she falls out of the tree. The others stop to discuss whether she was doing a good deed by saving him or if she was just so bloodthirsty that she wanted to kill one more creature before dying herself. You decide.