Opis: We open with a stormy sky as background and a narrator telling us, "Those who hunt by night will tell you that the wildest and most vicious of all animals is the tiny shrew...in March, first in Alaska, and then invading steadily southward there were reports of a new species, the giant, killer shrew."A supply boat cruises across an open sea, with Captain Thorne Sherman (James Best) and his deckhand and mechanic Rook Griswold (Judge Henry Dupree) discussing the weather and the ramifications of an approaching hurricane. They still have a few hours before they reach their destination--a small island inhabited by a research team headed by Dr. Marlowe Craigis. This is Sherman's first run to the island; he recently bought the concession from the previous operator, Ferguson. They secure the boat for the storm, then row ashore in a dinghy and tie up to a small pier. On a low bluff they spot a small group approaching, and Sherman observes that something seems strange about it. Sherman and Griswold approach the group. Sherman is immediately taken with Dr. Craigis' daughter, Ann (Ingrid Goude). Craigis (Baruch Lumet) introduces himself and shakes Sherman's hand. Craigis inquires as to the previous captain bringing them supplies, and is told, "I wouldnt know, I just bought his run." All the time Sherman stares, noticeably, at Ann. He hands the manifest to Jerry Farrell (Ken Curtis) who is holding a shot gun. Craigis tells Sherman after unloading supplies he wants to send his daughter back on the boat. To everyone's surprise, Sherman informs them that they are not leaving today or even unloading supplies. The approaching hurricane will delay everything. Sherman is growing suspicious, but can't really identify his concerns. He tells Rook that if he comes ashore later to wear a gun. The group, including Sherman, return to the house. Sherman is struck by how fortress-like the structure appears. He notices the radio antenna and asks if they were aware of radio reports about the approaching storm. He is informed the radio has been out of order for a week. At that moment, Mario (Alfredo DeSoto) opens the door on a 10-foot high fence and welcomes the group back. Ann suggests Sherman join them for a cocktail. Craigis tells Mario to mix them up some martinis. Sherman accepts and they step inside. They enter the patio compound, then the house and Sherman notices that Jerry very deliberately slams, locks and verifies locking the gate.In the living room, Ann, Sherman and Dr. Craigis enjoy their martinis. Craigis informs Sherman that they are self-sufficient: cows for fresh milk and chickens for eggs. Ann adds that they even have saddle horses. Sherman observes that they picked a lonely little island. Ann dismisses herself to go change clothes. Sherman tells Craigis that he suspects that the delay in departure isn't the only thing bothering Ann. Before Craigis can respond, his research colleague, Dr. Radford Baines (Gordon McLendon) walks into the room, so engrossed in his research papers, he is unaware they have a guest. Craigis introduces him to Sherman. Baines tells Craigis that two new litters were born and support their theory. Craigis apologizes for his colleagues strange behavior. He tells Sherman he is brilliant but absent minded. Sherman asks about his specialty and is told Baines is a Biologist, specializing in genetics and heredity. He also tells Sherman their objective, as practical research, is to decrease an animals size, but keep a low metabolism so an existing food supply will go further with a longer life span. Overpopulation is the concern, not now, but later. Ann, having changed into something less formal, returns to join her father and Captain Sherman. She asks to speak to her father, out of earshot of Sherman. Sherman finishes his drink. He asks if Craigis has ever been through a hurricane before. Craigis tells him they've only been on the island nine months and that prior to that the island was unoccupied for years. Sherman advises hurricane preparations, then talks to Ann about the weather. Ann tells her father she's invited Thorne for dinner, which surprises him, as they had no such conversation. Sherman declines as Baines comes into the room with a shrew in his hands. Craigis explains to Sherman that they are the subjects of the research. Sherman picks it up and comments that it "looks like a small rat, but smells like a skunk." When Sherman asks, how big do they get? There follows a dramatic pause, then Craigis tells him that it is an adult, but one look at Ann tells him that Craigis isn't telling him the whole truth. When a shutter crashes against the house, Ann screams. She is dying to tell Sherman the whole story.At the beach, we see Rook rowing back to shore with a check line from the boat. The hurricane is close to the island. Craigis explains the shrew's behavior, that when hungry, they'll tackle anything, regardless of size. Their metabolism is such that they need to feed constantly and will turn to cannibalism if necessary. Ann, visibly upset at the conversation, interrupts her father to ask for another drink. Mario escorts Sherman to the bathroom to freshen up for dinner. Mario asks whether or not he will be leaving tomorrow. Ann tells Jerry that his drunken stupidity has caused the problem they now face. Jerry let some of the shrews loose and they've grown into the monsters that now threaten the party. When Sherman enters the living room, Jerry leaves. They are engaged to be married, and Jerry suspects Ann is developing feelings for Sherman. Jerry comes back and he and Ann continue their earlier argument. Rook comes ashore with the check line and ties it to a tree near the beach. Hearing a strange sound, he spots something, pulls his gun and fires. A pack of dog sized creatures chases him into the woods. He climbs a tree and they jump trying to get him. He calls for help, but the wind, rain and thunder mask his screams. The branch he's on breaks and he falls into the pack, which finish him off.Sherman tells Ann he's going back to his ship. She tries to dissuade him, and finally has to pull a gun to stop his departure. Outside a pack of shrews is jumping on the fence. Ann tells him the truth about their research and the giant mutations they accidently created. "There are two or three hundred giant shrews out there, monsters weighing between fifty and and hundred pounds." Dr. Craigis enters the room and agrees that Sherman should be told the entire story. Six months before a litter of giant shrews escaped and began to breed. Their food supply is nearly gone, which is why they are waiting by the house. The shrews attack the barn and eat the livestock. Sherman goes outside because he thought he heard a human voice, Jerry follows and attacks him to keep him from opening the gate. Once safely back inside, they begin to plan their escape for the next morning. They must make it through the night first. As a precaution, they decide to patrol the house all night in shifts.At 3:00 a.m., Mario finishes his rounds and goes to get Jerry for the next shift. Jerry is very drunk and convinces Mario to take his shift. A shrew enters the house through a broken shutter in the kitchen. It goes down in the basement. Mario notices the broken shutter and secures it, but realizes a shrew is in the cellar. He goes to see Sherman to help him kill the shrew. Armed, the two search the cellar, but Mario doesn't see the creature hiding under the stairs. It attacks and bites him. Sherman shoots and kills it, but Mario collapses, apparently from blood loss. Sherman hastily improvises a tourniquet out of some cloth and his revolver. Ann has summoned help, and Craigis and Baines assist Sherman with Mario. Craigis pronounces him dead. Baines suggests hemotoxic syndrome, and Craigis concurs, but says that the autopsy will confirm the cause of death.Testing the animals saliva they discover that a poison they put out to eradicate the giant shrews was absorbed by the shrews. They now realize that a bite or even a scratch from one of them is lethal to anyone exposed. Ann explains to Sherman that she is a zoologist and that she also played her part in the research and is also responsible for the problem they created. Her specialty is their diet.The shrews find an entry into the house. Everyone is holed up in the living room. When they bait the outside, with the dead shrew that killed Mario, and it remains untouched for twenty minutes, they feel a run for the boat is now advised. Sherman and Jerry leave the house. Before they get too far, Jerry threatens Sherman with the gun. He is jealous, and Sherman quickly disarms him. They walk to the beach and call for Rook. They search and only find a few articles of clothing and conclude Rook came ashore and was killed and eaten. They return to the house followed by a pack of shrews. Jerry makes it back first and slams the gate shut, trapping Sherman outside to the approaching pack. Sherman shoots and kills a shrew, then scales the fence and attacks Jerry. He gives him a severe beating, then carries him up and prepares to throw him over the fence to the pack. He comes to his senses and puts him down. Back in the house he explains to Baines and Ann that Jerry twice tried to kill him and he had it coming. He also informs them that Rook is dead. Craigis helps Jerry inside and puts him on the couch. Ann opens the kitchen door to make some coffee and lets a shrew into the living room. It bites Dr. Baines, who sickens and dies very rapidly. Sherman dispatches it with his revolver. Jerry is visibly shaken and starts to drink again. He picks up the revolver and starts firing into the kitchen door, wasting a lot of ammunition. A shrew starts digging through the wall into the living room. Jerry is now very drunk and hysterical. It is now apparent that the only safe place is the patio, with the roof as a last refuge.While barricading the wall to the house, they discover some metal drums or barrels. Sherman sees them as a means of escape. He proposes to lash them together, get inside and walk down to the beach and swim out to the boat. He finds a welding torch and cuts eye holes into the barrels. They quickly rig a rope to the gate and prepare to leave. Jerry goes up on the roof and refuses to join them. When they notice a shrew digging through the wall into the patio area they decide to leave Jerry on the roof and escape. They get inside the barrels and open the gate. They are immediately set upon by the pack. They walk to the beach, then out into the ocean. When the water is deep enough they escape the barrels and swim to the boat. Once Jerry sees no more shrews he comes off the roof and makes a run for the beach. He only gets a few hundred yards when he is attacked and killed by another pack. Ann, Sherman and Dr. Craigis climb aboard the boat. Craigis explains that with no more food the pack will turn on itself, and the last one will then die of starvation. Ann and Sherman kiss.