Pam is embarrassed when she is the only person at corporate wearing a costume on Halloween. Holly and Michael take the long trip to Nashua after they get some shocking news from corporate. Meanwhile, Dwight torments Andy and tries to get under his skin.

The Dunder Mifflin staff head to Niagara Falls for Jim and Pam's wedding, with the understanding that her pregnancy is a forbidden discussion topic, but Jim's slip of the tongue prods Michael to attempt damage control.