Wesley leaned over to looked over Rupert's shoulder when he called up another book, his mind going back to his studies at the academy when the other man mentioned the dimension with the ghost-like demons. Sometimes, they managed to escape from their dimension and manifested as what people called poltergeists. Most of the time, when "hauntings" by those demons stopped, it was because they had returned to their own dimension, either by their own choosing or from banishment. Banishments were few and far between though, from what he remembered.
And Wesley had a feeling they were discovering why.
The amulet Angel had given Buffy was from that dimension. If it was one of the few things that could banish those sorts of spirits, maybe that was why it been used against the First. Wesley had a feeling it had been used to pull the First and its minions into that other dimension. But, of course, the wearer had to go with them after living through an extreme rise in temperature to actually activate the portal.
The pieces were starting to come together. Especially where Wolfram and Hart was involved.
Lookng over at the spell Rupert pointed out, Wesley nodded, taking note of what was needed. "Most of those are available in the magic stores here in the firm," Wesley said. "This, though..." He pointed to one of the ingredients. "We don't have."
"That's easy enough," Martin said, standing up and looking at what Wesley was indicating. "It's created from a chemical reaction between Xenon and a demonic heavy metal called Relaticq. You wouldn't have any to hand because it's notoriously unstable and has to be used within two hours of creation or it goes bad."
He looked over at Fred. "Do you have a pressure chamber in the lab? We can use it to make this if you have the Xenon and Relaticq. If you don't have the Relaticq, we have some at the Council lab - we could have it sent here."