Charlie and Jimmy end up at Treasure Island, at the 1939 San Francisco Exposition. While on a plane, a well known writer dies and his death is suspicious. He is connected to someone or something called Scorpio. Charlie must inform his wife of his death. This leads to the detective dealing with a couple guys who have a connection to a mystic whose name is indeed Scorpio. There seem to be a lot of cover ups as they wade through the case. Charlie is accompanied by a couple guys. One is really annoyed that his serious girlfriend is under the spell of this mystic. This is quite a good presentation because of the seances and the intrigues of the netherworld. There is one great scene where the young woman, who does a mind reading act senses murder in the room.

A friend of Charlie Chan's dies on a flight to San Francisco, leaving behind cryptic clues about someone called Zodiac. Charlie discovers it's Dr. Zodiac, a phony psychic who may also be a blackmailer responsible for driving several people to suicide. So he investigates with unwanted help from "Number Two Son" Jimmy (Victor Sen Yung).Some really good support for Sidney Toler in this one. Victor Sen Yung provides the comic relief as Jimmy. Douglas Dumbrille, Donald MacBride, and Douglas Fowley were all fine character actors I always enjoy seeing. Cesar Romero has one of his better roles from the '30s. Also Sally Blane, aka Loretta Young's sister, plays Stella. Considered by many to be the best of the Toler Chan films. I would have to agree with that. The cast, interesting setting, and supernatural elements combine to make a very entertaining movie.

While in route to San Francisco, Chan's friend Paul Essex dies of an apparent suicide. The only clue is a threatening note from someone calling himself the Zodiac. Chan soon discovers that the Zodiac is a successful mystic. Together with a would-be psychic-buster and magician named Rhadini (Cesar Romero), Chan sets out to discover the source of the Zodiac's mysticism and unmask a killer.I thought I had seen the best of the Charlie Chan series. Man, was I ever wrong. After a first viewing, Charlie Chan at Treasure Island has become one of my very favorite Chan films. It's not just one of Toler's best, it's one of the three or four best entries in the entire series. It's got everything a fan could ask for – an interesting plot, a larger than life villain, solid acting, compelling characters, real suspense, comic relief that's actually funny, and some of the best writing I've seen in a Chan movie. The final reveal is also one of the best in the series. It's not the usual drawing room gathering of the suspects (which I usually prefer), but a drawn out, tension filled scene in a theater full of people. And speaking of tension, Chan's first meeting with the Zodiac is amazing, if not a bit frightening. Charlie Chan at Treasure Island also benefits from a strong supporting cast. Cesar Romero, Douglas Fowley, Pauline Moore, and, personal favorite, Douglass Dumbrille add considerably to the film. Overall, this is one Charlie Chan film that I'm very much look forward to revisiting – and soon.

"Charlie Chan at Treasure Island" is at the top of many Chan fan lists as their favorite; it certainly deserves that distinction. Even when the film gets creepy it's fun, as in the séance scene at the home of Dr. Zodiac.Charlie Chan's friend Paul Essex is an apparent suicide aboard a San Francisco bound plane flight. His suicide note - "Can't escape Zodiac, Good Bye my Love, Paul".Charlie Chan (Sidney Toler) is warned not to investigate: "Do not challenge the supernatural unless you are prepared to visit your ancestors." But investigate he does, and as usual we are introduced to a colorful cast of characters and suspects along the way. There's The Great Rhadini (Cesar Romero), who challenges other magicians and psychics, his mind reading assistant Eve Cairo (Pauline Moore), and insurance investigator Salsbury (Douglas Dumbrille). Aiding Charlie on the case are Number #2 Son Jimmy (Victor Sen Yung) and Deputy Chief Kilvaine (Donald MacBride).Watch for a neat scene when Chan returns to the Zodiac home a second time - a black cat crosses his path.The twist to the story comes when we learn that Romero's character Rhadini is also Dr. Zodiac, blackmailing victims with secrets from their past. He even takes a knife to the shoulder during an on stage performance in an attempt to throw suspicion in a different direction. The film borrows from a Bela Lugosi trademark, piercing dark eyes attempting to overcome psychic Eve Cairo's thoughts while under Chan's influence to flush out the killer of Zodiac's Turkish servant.The film is set against the backdrop of the 1939 San Francisco World's Fair, Treasure Island being an attraction, along with the Century of Progress Exhibition. But as in most of the Charlie Chan films, the locale is secondary to the mystery, and this time it's a good one, with clever writing and just enough imagination to make you wonder whether mind reading might actually be real!