The Committee, with specially invited guests, gathers in Mrs. Quennell’s house for Grace’s hypnotism. The audience includes the Governor’s wife, Lydia, and Reverend Verringer. Simon is skeptical but secretly wants to be amazed.

Dr. DuPont leads Grace in and seats her in front of them; they are all seated around a large table. He explains that he’s simply going to put Grace into a neuro-hypnotic sleep. Grace seems terrified, but not of Dr. DuPont. DuPont tells her that when she wakes up she will have no memory of what happens, and Grace seems to fall into a trance.

Simon tells DuPont to ask if Grace ever had “relations” with James McDermott. Grace answers in a voice that doesn’t sounds like her own; she mocks Simon. She says that she didn’t sleep with McDermott, but instead teased him and led him on, along with Mr. Kinnear. She admits that she strangled Nancy with her kerchief. Just as everyone is bemoaning Grace’s guilt, as they all had believed her to be innocent, Grace announces that “she,” the voice speaking, is not Grace. Grace did not know anything about it.