Grace Albertson

Embarrassed when he forgets a client's name, Darrin buys a book to improve his memory. Endora slyly casts a spell on his watch so that when he wears it, Darrin has a perfect memory. Ed Pennybaker, a client, prides himself on his vast knowledge, but Darrin tops him every time. When Darrin takes off his watch, he forgets things, but doesn't get the connection. Samantha invites the Pennybakers and the Tates to dinner. Ed displays his expertise on every subject, but Darrin easily outshines him. Samantha realizes that Darrin may antagonize an important client. She tries to stop him but fails.

Mike's new college girlfriend, Mary Beth (Jena Engstrom), seems more interested in Steve (Fred MacMurray) than Mike (Tim Considine). She wants Steve to help her with her trigonometry class.

Mannix can't find the lady who he saw being attacked in her yard by 2 men, but he does find out that a woman was murdered there under the same scenario a year before.

A series of reports by eleven year old Custer to his father, Mayor Ulysses S. Jamison on the strange feats of magic at Tony's house results in the Mayor taking his son to Dr. Bellows, the base psychiatrist. Bellows tells Custer he believes his story and asks him to keep a close watch on Tony A policeman catches Dr. Bellows and Custer peering into Tony's window and takes them inside for identification. While Bellows is telling Tony that Custer believes he has seen them levitate, Jeannie causes him to do so. Bellows bows out, feeling he has stumbled on a top-secret aerospace project. Tony voices his nervousness to Jeannie about being spied on by Custer. When Custer disappears, Tony accuses Jeannie of turning him into nothing. Angered, Jeannie leaves. Later, when Custer comes back, having spent the day at a carnival, Tony penitently begins searching for Jeannie. He is sure Jeannie has joined a carnival act and starts a riot at the sideshow when he mistakes a veiled woman for Jeannie. Jeannie returns home and starts pulling down all the shades to outwit Custer.

The wife of a wealthy industrialist disappears from their sailboat off the coast of Mexico, and he initially hires Mannix to learn how she disappeared (and partly because he knows that a husband is usually the primary suspect in the disappearance of a wife).