Atop the Witch’s Tower Lay the Necromancer’s Gate.
Upon reaching the top of the tower, the party were greeted by fresh dead corpses. There they also met foul traps. One trap claimed the life of Mercer, the HalfGnome Thief. Saddened by the loss the party moved on to see what was going on. Atop the tower they found dark clerics guarding the inner sanctum.
Within the Sanctum, a strange contraption, massive bronze gears without spokes. They appeared to be holding a portal. This portal, was surrounded by a field of glowing magic. This magic flowed from four large and bizarre orreries, into the desiccated corpses of four witches, trapped in the rigour of death, frozen in agony, holding the shield in place. One such witch held a staff. Near her, was a familiar villain. The cleric from the Tomb of Blood, Veltargo was present. He engaged in combat with the party, but was not willing to hang around.
He grabbed the staff from the master witch and using a word of recall vanished, taking the staff. The energy holding back the portal exploded out, and with it the portal energies consumed the party.
Pain, a whirling sensation and an endless darkness. Unconsciousness.
Eventually the party awoke. They found themselves in a very small room; barely enough space for them all, and not tall enough for some. Most disturbingly, the room had no doors or entrances. No manner of ingress or egress.
A quick look around showed that the walls were of different materials. Picking the weakest the party started to bash their way down.
No sooner had they created an opening than it was filled with a large eye, a heavily accented voice spoke out and demanded to know what was going on. The odd creature before them was cube shaped an appeared to be made of brass and copper. This Modron resented the invasion of his bedroom. Soon the party found themselves out on a most peculiar street.
The party were now in Sigil, the city of doors and the accepted center of the Multiverse by anyone who isn’t a God or a Signer of One.