Where's the Apostrophe?

I asked myself when I saw a pretty black woman wearing a shirt that said

"Black's Where Its At"

And I thought, I musta read that wrong.... but noooo, that's what the shirt said. Now, I'm not the literary genius type, you can find plenty of errors here without even trying very hard... But I don't make T-shirts for a living. So what's wrong with the shirt? Shouldn't there be an apostrophe on the "its", isn't that word supposed to be a contraction? If not, then the word "its" is the object/subject of "black" or something. I tried to make the sentence make sense, but I mustn't be smart enough...

Or is there some secret place called "Black" where I can find that elusive thing, that "it", that we can ever seem to remember?