The door to the north leads to what once was the way to the stables. The hall is straight and goes through two sets of double doors. The hall is plain, with just small niches for light stones or lamps. The trap lays between the two sets of double doors. The DC to find the trap is 25 and the disable it is also DC 25. When someone steps on the pressure plate in the middle between the two sets of doors the doors lock and then sand begins to poor in and until it fills to almost the ceiling. After the "fill" line is reached after 20 minutes the sand drains away, the trap resets and the doors unlock.
Past the second set of doors is what use to be the stables. There enough room for 20 mounts and hay and grain for a good month for them. There is a stone trough at one end that still holds drinkable water and if a detect magic is cast will show it has a conjuration spell laid upon it. Moss and mushrooms grow on around the trough. There are skeletons of horses in some of the stalls and one human skeleton with a spear through the rib cage pinned in one of the stalls.
The party will also find a single ghost in here as well. Two things can happen. Either the party attacks and take care of the ghost that way, or they can talk to the ghost. The ghost is the ghost of the stable hand pinned in the stall. He tells a sad tale of trying to save his horses from the House war party and tried to explain he wasn't trying to help the wizard, but no one would listen to him and killed him. The raiding party also just left the horse sealed in since they saw the horses as tainted. This is what saddens the ghost the most, not his death. The ghost will not attack the party first, but will wait to see what they do.