This episode marks one of the most recent appearances to date by Michael Blue and Kres Mersky. Jane Windsor had acted in several productions during the 1980's, before returning to college. Larry Linville has since unfortunately passed.
In a Subcontinental Indian cavern, an Explorer (Michael Blue) and his Indian guide, Vikram Singh (Kabir Bedi), discover a ruby, the "Seeing Eye of Daanau," embedded within the powerful golden cobra, which comes with a curse to all who would dear to wear it. The Explorer immediately perishes upon removing the ruby from the golden statue.
After an unspecified span of time, the Daanau gemstone is set into a golden necklace, purchased by the wealthy Richard Hazlitt (Richard Bradford), who presents it to his young British-born bride, Alice Davies Hazlitt (Jane Windsor), at their Maryland estate, while preparing for a day of festivities, including a Polo match and party set for that evening.
Doctor Seth Hazlitt (William Windom) has been estranged from his brother for thirty years, in the aftermath of a triangle, in which Richard and Seth each sought the affection of Molly, with whom Richard had eloped, causing Seth to relocate to Portland, Maine.
Seth had subsequently married the now-late Ruth and forgotten about the now-late Molly, who had born two children, the determined Mark Hazlitt (Douglas Barr), who cannot seem to please his father in operating the family business, and the irresponsible Carolyn Hazlitt (Jane Badler), who amasses more debt than she can manage through her extravagant spending.
Joining the Hazlitts for the Polo match and party are Bert Davies (Clive Revill), the possessive father of Alice, and Vikram Singh (Kabir Bedi), now the Cultural Attaché at the Indian Embassy in Washington, DC, who seeks the return of the Daanau to its rightful owner, the government of India, and communicates its dreadful curse to anyone who wears it.
After Seth Hazlitt and Jessica Fletcher (Angela Lansbury) pay a visit to their unseen U.S. Representative from Maine, Congressman Everett Hale, Head of the House Committee on Secret Intelligence, Seth informs Jessica of the invitation which he has received to visit his brother in nearby suburban Maryland. When Jessica encourages Seth to accept the olive branch of peace, Seth places the condition that Jessica join him for the event. (There is a reference here that Richard, Mark and Carolyn are Seth's only surviving relatives, but in a future episode, Jessica joins Seth on a visit to his cousin's estate in South Carolina.)
At any rate, when Richard acts surprised to face Seth, who mingles with Alice, Bert and Jessica after the Polo match, Alice explains that it is she who sent Seth the invitation, and welcomes Seth and Jessica to stay as their guests. Richard saves face by agreeing with Alice and Jessica's suggestions that the brothers Hazlitt are overdue for a long talk to patch up their differences.
But during the party that evening, when Alice excuses herself to retrieve her present for Richard from their garage, she becomes trapped when the door is locked behind her, with carbon monoxide fumes from the operating automobile, which also has a locked door, to prevent her from extinguishing the exhaust, thus supplying evidence toward the "Curse of the Daanau."
Everyone acts very suspiciously before and after Alice manages to recover under Seth's medical expertise, and Richard and Seth manage to reflect over their past differences to resolve them--or at least until a body is discovered in the locked study, from which the Daanau has been stolen.
Lieutenant Steven Ames (Larry Linville) investigates the attempted murder, and returns to investigate the murder, yielding to Jessica's expertise as a perceived government secret agent.
The cast is rounded out by Policewoman (Kres Mersky) at the precinct office, and Police Officer (Michael McNab) at the Hazlitt estate.
