Darrin is planning on buying a present for Samantha just because he loves her. Endora believes the gift is to ease a guilty conscience for something he's done. She also believes that mortals can't stand to tell the truth. So what Endora does is secretly place a spell on the gift - a unicorn broach, unicorns which are Samantha's favorite creatures - so that any mortal within vicinity of it has to tell the truth. Although the spell causes a few issues for Darrin, the biggest issue may concern what is already the problem account of Cora Mae Sportswear as the spell dictates how Darrin and Larry deal with overbearing Cora Mae Franklin, the company owner, and her henpecked husband, Walter Franklin.
—Huggo