I've reloaded many different saves but when I get to Samuel at the docks to start the "Lady Boyle's Last Party" mission, he just stands there. Sometimes he tells me to go find Pierro, who may or may not be peeping at Callista, but talking to him doesn't change anything. Samuel still stands there with no option to talk to him.

I'm stuck at the Hounds Pit Pub and cannot carry on! Is there something I'm missing, or is this some weird game breaking bug?