Bruce Davison stars as social misfit Willard Stiles, who is squeezed out of the company started by his deceased father.

After leaving the party in embarrassment, he notices a rat in his backyard and tosses it pieces of his birthday cake.

Willard asks Al for a raise, having not received one since his father's death, despite working after hours and weekends.

Willard sneaks into a party that Al is hosting, opens a rat-filled suitcase, and urges them to get the food.

After overhearing one of Al's friends boasting of a large cash withdrawal, he sneaks into the man's house and orders his rats to tear up the bedroom door.

[7] Variety said: "Neat little horror tale...some good jump moments, at least two stomach-churning murders committed by the rats, and superior production values with tight direction of Daniel Mann develop pic into sound nail-chewer".

[9] Gene Siskel of the Chicago Tribune also gave the film 2 out of 4 stars and wrote that although it "will have you keeping your feet up off the theater floor, Daniel Mann's slow direction will lower your eyelids.

[10] Kevin Thomas of the Los Angeles Times wrote that "one could not ask for a more satisfying, yet less pretentious hot-weather suspense-horror entertainment.

With its disturbed young hero, crumbling old mansion, and macabre developments, it immediately brings to mind Psycho.

The more apt comparison, however, is with that much-cherished English comedy of some years back, The Green Man, in which Alastair Sim (at his drollest) went around blowing up a series of troublesome types".

[11] Tom Milne of The Monthly Film Bulletin thought that the rats were "so well-mannered and prettily groomed that they are more likely to elicit coos of delight than shudders of fear...when the horrors do come, they are very tame indeed: not one single shot to match the chilling menace dispensed by the brooding crows in The Birds or the prowling felines in Eye of the Cat.

Instead, Daniel Mann settles for facile effects, like the cut-in shot of rats tearing at a piece of raw meat while they are supposedly demolishing Ernest Borgnine, and gradually drives what might have been an unusually intriguing horror film pretty much into the ground".

[12] Leonard Maltin gave the film 2 out of 4 stars in his annual home video guide, writing: "Touching story of a boy and his rats captured public's fancy at the box office, but [the] film's lack of style prevents it from being anything more than a second-rate thriller".