It's a classic combination - cat, mouse, dog. The cat is trying to catch the mouse but the mouse is smart enough to know that it should use the dog as cover. The cat has to get to the mouse without the dog getting to him.
It is very much a classic combination - as Roger Meyer says in The Simpsons `the animal food chain goes, mouse, cat, dog'. Warner Brothers basically gives us what many will recognise as a well used set up from the Tom & Jerry cartoon. What this means for the audience is that it is a better version of T&J if you happen to like the unique sense of humour that exists in most of these WB cartoons.
The plot is nothing unique but the delivery makes it better, with the jokes actually being quite inventive rather than just the usual chase stuff. The characters are mixed. The dog is a straight lift from every bulldog of every cartoon, however both the cat and the mouse are slimmer and a bit sharper in terms of wit - they may lack a little in the way of well known character, but I think they delivered well.
Overall this may not be new ground that WB was breaking but he showed that they could take any type of cartoon and, with a few personal touches from talented writers/directors, that they could refresh it with their unique brand of inventive humour.