Good casting (although Thayer is 'way too thin), good chemistry and decent production values yield an enjoyable ninety minutes. The plot, in a nutshell: a wealthy woman, harassed by the FBI, hires Wolfe to get them off her back. His chance to earn his $100,000 fee improves when he learns that three agents may have been involved in the murder of a reporter who was working on a story about the Bureau.
As is often the case with Wolfe stories, the real interest lies in the characters -- Wolfe's methods and Archie's charm -- and the mystery itself, while it hold up, is almost incidental. The book from which it was adapted, "The Doorbell Rang" (1965), is generally considered the best of the Wolfe books.
This made-for-TV film was reportedly a pilot; a series never resulted but four years later NBC presented William Conrad as the first (and, one hopes, the only) bearded Nero Wolfe. Conrad had a remarkable career in radio and TV, but he was miscast and the show lasted fourteen episodes. A&E reran those some years ago, but when was the last time anyone showed this film? If it was ever released commercially, I couldn't find a trace of it.
