It was about a female scientist working on a shrinking device and testing it on her friend and restoring her after the end of each experiment.
But one evening, the female friend shrinks herself by accident without the female scientist around, and a male scientist happens to enter the house, looking for what his competitor was working on.
The male scientist finds the shrunken friend and starts toying with her, drunk on his power over her. He ambushes the female scientist when she returns and shrinks her too, and puts one of the females tied up in a hamster cage.
He spends the night toying with the shrunken females (2 or maybe 3, I don't remember)
In the end, they defeat the male scientist and unshrink themselves, and the girl who was put in the hamster cage releases it into the wild
That's about all the details I remember