Darrin (Dick York/Dick Sargent) and Samantha Stephens (Elizabeth Montgomery) are a young, bi-species married couple: he's a mortal human being, she's a witch, something which she does not divulge to him until after their wedding. Darrin just wants them to live a simple, mortal life, to which Samantha agrees, meaning no witchcraft and no telling any of their mortal friends and relatives of her being a witch. However, that no witchcraft vow is difficult to maintain if only because of Samantha wanting or needing to use it to get out of one scrape or another, and her relatives, especially her mother Endora (Agnes Moorehead), the most constant thorn in Darrin's side, against the marriage and the idea of denying Samantha's heritage as a witch. Mortals in their lives also add to their complicated lives: Darrin's friend and spendthrift boss, Larry Tate (David White) of McMann and Tate Advertising, who always wants Darrin to do all the work while the company gets all the glory and money; their nosy neighbors, the Kravitzes, Gladys Kravitz (Sandra Gould/Alice Pearce), who always arrives at the most inopportune time to show her exasperated husband Abner Kravitz (George Tobias) that something funny is going on in the Stephens house; and Darrin's parents, his mother, Phyllis Stephens (Mabel Albertson), who is prone to splitting headaches which become more prevalent as she thinks she sees things in Samantha that just couldn't be in her mortal view. That complicated life gets even more complicated when they start a family, the children who could be mortal or who could be witches and warlocks.