Agatha Christie's legendary detective, Hercule Poirot, is back on American television, and Peter Ustinov has once again captured his essence. Agatha Christie's ``13 at Dinner'' (CBS, Saturday, Oct. 19, 9-11 p.m.) is vintage Christie, filled with intricate plots, counterplots, and alternate plots . . . complete, like the cherry on a hot-fudge sundae, with one final extra twist to top it off. Don't expect me to recount the story line. Like all Christie scenarios it is overflowing with improbable characters involved in suspicious proceedings who turn out to be totally innocent of any wrongdoing, while the guilty party is the one you least suspected. This plot is especially unlikely -- but who cares! It's so much fun to watch the shrewd Hercule unravel it that one tends to forget just how outrageous the whole charade is in the first place. And confusingly intricate, too.
In addition to the delightful Ustinov as Poirot, ``13 at Dinner'' has the advantage of authentic London locations and Faye Dunaway in a dual role, playing a Marilyn Monroe-ish actress as well as someone who does a marvelous impersonation of her.
``A good crime is like an omelet,'' Hercule pontificates at one point. ``You only discover its faults when you put your fork in it.''