Bathtub clogged - Is there DIY help?

I’m pretty sure the tub is clogged with kitty litter.

I say that because it’s in the bathroom we never use, so there’s no logical reason for it to be anything else.

We use plain clay, non-clumping litter. I was just trying to clean the tub, and lo and behold, nothing’s going down the drain.

I’ve tried plunging, pouring boiling water down the drain, and fishing around with a coat hanger, and all combinations of the above, to no avail. It’s 11:00 PM, and I’d like to get it fixed ASAP, if possible.

Help?