Mrs. Capon is Mrs. Boring's cousin. Mrs. Capon joins David, his mother and Dot at Hulligan's Wharf. She is Canadian. She has one daughter, Iris, who is 16. Mrs. Capon takes a special interest in David, such as changing his bandages.
One night, Mrs. Capon seduces David and puts the lucky penny necklace David had made for Wanda around her neck. At some point that same night, Mrs. Capon ends up missing and they only find the capsized boat that belongs to the island. Later in the novel, two fisherman pull Mrs. Capon's dead body out of the water and an investigation into her murder ensues.
