What was the shadiest thing Caroline ever did?
There are so many shady things Caroline did, but I really think the worst was when Laura got pregnant and Caroline turned to Charles and said "Oh Charles! We're finally going to become grandparents!!!" Um, Caroline, you already had a grandson! It wasn't his fault Mary and Adam neglected him and got his neck broken by a window and was burnt to a crisp. That really showed her true colors, and was quite hilarious how sociopathic she really was.
An honorable mention was her doing a menage a trois with the Gallender brothers, and to save her reputation she told Charles she was attacked knowing that hot-headed Charles would go over to the brothers' place and get his butt kicked by them, likely to have another round of broken ribs!
So shady!!!