We just adopted two 3 year old Siberian cats (brother and sister) from a woman who had had them since they were born. She was heartbroken to part with them and apparently so are they. During the first five hours of being in my house they have been hiding under the couch. Right now there's still there. They have not explored the rooms, haven't gone to the litter box or haven't eaten or drunk anything. Help! What do I do for them??
Yes exactly.
Once I had to take a road trip from Germany to Malta since moving down there meant getting the car down... so all 3 cats in the back seats. They had food, water and litter boxes at the bottom so they could get to them without a problem. The trip took around 4 days and only on the last day did they actually eat and poo. So it's just something natural that when they're not in their normal surroundings their needs change. But they will come around eventually I am sure, so patience is the biggest gift you can give them right now.

Good luck!
Hello anon,
How much time did their trip take? Looks like they are still very stressed and scared. Give them some time to realize no one is about to hurt them... do you have any things from their previous home? Maybe some toys or bedding, even their old bowls, or something that would remind them of the lady they loved so much. Familiar smells should help them adapt sooner, so it'd be nice if you could get some of such things. But do not try to speed up the process... let it be natural! I'm sure everything will be fine eventually, cats are very sturdy creatures!
 Punkybrewster's reply was promoted to an answer.
Thanks for your advice! Now they at least came out and started exploring the room cautiously. I'll try to get some of the old things they're used to, Lauren. I should have thought about it before but I've never owned a cat even though I've always wanted to. Now I'm happy and I hope they will be as well!