The Evil on the East River

From the introduction:

The Investigators have come to the attention of A’lelia Walker as people of interest. This can be through a personal introduction by a thankful third party, for services rendered, or because Walker has heard of their heroic exploits around New York.

She has invited them to one of her legendary parties at Walker Studios at her grand townhouse on 136th Street.

Walker herself might also be attracted to any Investigators with a high APP. Regardless, by the end of the night, she invites them to accompany her at the next party aboard the steamboat, going down the East River bound for Boston.