The depletion of the earth's ozone layer causes animals above the altitude of 5000 feet to run amok, which is very unfortunate for a group of hikers who get dropped off up there by helicopter just before the quarantine is announced.
| Actor | Role |
|---|---|
 Christopher GeorgeSteve Buckner | Steve Buckner |
 Leslie NielsenPaul Jenson | Paul Jenson |
 Lynda Day GeorgeTerry Marsh | Terry Marsh |
 Richard JaeckelProf. Taylor MacGregor | Prof. Taylor MacGregor |
 Michael AnsaraDaniel Santee | Daniel Santee |
 Ruth RomanMrs. Shirley Goodwyn | Mrs. Shirley Goodwyn |
 Jon CedarFrank Young | Frank Young |
 Paul ManteeRoy Moore | Roy Moore |
| WWalter BarnesRanger Tucker | Ranger Tucker |
 Andrew StevensBob Denning | Bob Denning |
 Susan BacklinieMandy Young | Mandy Young |
 Kathleen BrackenBeth Hughes | Beth Hughes |
| BBobby PorterJohn Goodwyn | John Goodwyn |
 Michelle StacyLittle Girl | Little Girl |
| MMichael AndreasSheriff | Sheriff |
| JJan Andrew ScottHelicopter Pilot | Helicopter Pilot |
 Gil LambOld Man in Bar | Old Man in Bar |
 Garrison TrueTV Announcer | TV Announcer |
| GGertrude LeeRanger's Wife | Ranger's Wife |
 Walt GorneySam (uncredited) | Sam (uncredited) |