Which Supernatural Episode was this?

Ok, well it was the first episode I ever saw and I wanna know which one it was:

So this family bought a house somewhere and I think it was a little kid that kept saying the house was haunted. It turned out the kid was right and (I dunno how Sam and Dean got there((I haven't seen it in ages)) but they were there.) Sam and Dean where there and it turned out this person thing wasn't a ghost at all but some kind of dead undead human. And it wasn't just her it was her brother too, and they eat a rat in one part and they kidnapped the little boy i think it was, and i guess the old story was...:

Some old dude got his daughter pregnant(ick) and so he tried to kill her by locking her away in a basement and building a wall over that door and it turned out she had twins I guess and after she died they were still stuck down there with no light, so they just adapted to no light and they eat rats and they traveled through the walls.

Anybody know what Supernatural episode I'm talking about? And possibly what season?