The shrews (the result of an experiment gone wrong of course) have run out of other food and now are after human flesh. It's all very B-movie and low budget. The killer shrews are kept obscure for much of the movie probably because when they are finally shown they are completely ridiculous: basically barely disguised dogs.
All pretty formulaic and total nonsense but quite a lot of fun and at times quite scary. The human tank is genuinely innovative.
