Nyankees is a manga based entirely on a pun.
The sound that cats make in Japan isn’t ‘meow,’ but ‘nyan.’ The rough and tumble gang member types we might call hoodlums or delinquents are called ‘yankees’ (it’s a borrow word.) Put them together and you get the concept for this gag manga: cat delinquents… or delinquents who are cats.
The story is just about as dumb/awesome as you’re expecting.
I feel, in fact, like trying to tell you the plot of this manga is kind of self-defeating: alley cats, portrayed as people (and sometimes as themselves,) get into fights over food, territory, and lady cats.
That’s the whole thing.
Our hero, Ryuusai, is also looking for revenge on some one-eyed tom that gave him hassle or some such, but WHO CARES???
The point of this manga is not its non-existent plot. The point of this manga is to have fun imagining what cats might look like if they were people and how these people would act if they were actually cats. That’s literally it. Because at one point, Ryuusai gets stuck in a box that he figured he should be able to fit in because he could sort of sit in it–and we see all of this play out (or most of it, anyway,) with Ryuusai as a people.
You should totally read it.