"The midnight gatherings were held at the Witches' Brew, an old tavern made entirely of twigs and mulch that sat in the middle of the creek like a giant beaver dam."
In Beyond the Kingdoms, Alex, Conner and her friends infiltrate one of the witches' meetings hoping to catch the Masked Man. He shows up with some of his soldiers and the confrontation results in a big fight between the witches, the Masked Man and his soldiers on one side, and Alex, Conner and their friends on the other side. The tavern is destroyed by Alex when her magic causes to lift it high up in the air and then crash down to earth.
Several of the witches meeting there are mentioned by name. For more about these characters, see their character page.