With the investigation scratching at a web of old crimes originating inside the building, a mysterious young man turns the tables to spy on Charles, Oliver & Mabel.

Mabel’s incident on the subway leads her to gain help from an unlikely ally. Their journey takes them to a legendary amusement park which turns out to be full of terror — while amusements and evidence reside back in the Arconia with Charles and Oliver.

Charles finds an unexpected source for a major clue. A Broadway icon comes knocking at Oliver’s door. And Mabel forms an alternate trio to pursue a lead that sheds light on Ben’s bro and CoBro history.