The Extraordinary Reason Your Cat Runs Around Like Crazy At 3 a.m.

3 a.m and all is quie... wait, what on earth is that noise?! 

Wake up!

It's three in the morning and you are lying in bed listening your beloved cat running around the house. She's racing up and down stairs, opening the curtains, renovating the kitchen and baking a cake from scratch... at least that's what it sounds like! 

Next thing you know, she's worming her way into your bedroom, still and quiet, and ready for a snuggle. What's going on here?