InputStream from Assets folder on Android returning empty

I'm not getting any exceptions, but when I run...

InputStream deckFile = context.getAssets().open("cards.txt");

Then, deckFile.read() returns -1. The file is in the correct folder, and it is NOT empty.

This should be the easiest thing in the world...

EDIT: The AssetManager is indeed listing "cards.txt" as being there, so that shouldn't be the problem.