When you get to Houston, you have to go thru Immig. 1st. Then they shuttle you to claim your luggage (YOU HAVE TO DO THIS - IF YOU DON'T CLAIM YOUR LUGGAGE IT WILL JUST SIT THERE FOREVER). You put them on a cart, wheel it about 10' to customs, they ask you if you have anything to claim, then wheel it about another 10' and whatever airline you are flying on will take it and see that it gets to where it needs to go. It a pain, but it doesn't really take very long once you actually grab your stuff off the carousel.