Sci-fi fans may be perturbed to discover that "The Arrival" is not the serious "searching for aliens" movie it appears to be.

If you've seen the ads for this film in theaters or on television, you know that Charlie Sheen is shown to be an obsessed NASA astronomer who connects with a mysterious message from outer space only to see his superiors destroy the evidence and deny it ever happened.

But don't go into "The Arrival" expecting something on the order of "Communion" or even "Hangar 18." Think more "Invasion of the Body Snatchers" or "Invaders From Mars" - and in the end, even more specifically, the old TV series "The Invaders."

Sheen and his partner, Richard Schiff (who might as well be wearing a sign that says, "I'll be dead soon"), are working late one night when the transmission is received. They excitedly report to their boss, Ron Silver (who might as well be wearing a sign that says "villain"), but he puts them off and secretly destroys the tape.

The next thing you know, Sheen is fired and branded a disreputable scam artist. So he gets a job working for a satellite-dish company, rigs his own contact-the-aliens-at-home equipment and tries to reach extraterrestrials on his own.

Before you know it, mysterious, zombie-like villains (can you say "pod people"?) begin tracking his activities and killing his friends. So, Sheen heads down south, links up with a scientist (Lindsay Crouse) doing research on global warming and discovers that aliens based in Mexico (get it?) are hatching a take-over-the-world scheme.

"The Arrival" has several pulse-racing scenes, well handled by first-time director David Twohy (best-known for his screenplays "The Fugitive" and "Waterworld"). But they are in service of a plot that makes no sense.

In addition, there are lots of puzzling moments along the way: Why would aliens with super intelligence attempt to kill someone simply by placing scorpions in a hotel room (and how did those scorpions get up on that fan)? What's all that weird, gee-whiz stuff that Sheen encounters when he goes into the aliens' underground headquarters? And why don't the aliens enclose their elevators so they won't fall out?

The special effects are pretty good and the aliens are interesting (they have flaps on their heads and their knees bend backwards). And how about that floating ball that cleans up a room in no time - to include ripping up the carpet and stripping the paint off the walls. (The latter may cause horror fans to think of the killer ball in the "Phantasm" movies, or even the puzzle box in the "Hellraiser" series.)

Sheen isn't unappealing, though he has too many scenes that allow him to emote simply by bugging out his eyes and painfully grimacing. Silver plays his low-key villain no differently than he has in too many movies before and Polo and young Tony T. Johnson are simply doing stereotype riffs. Surprisingly, Lindsay Crouse, who generally comes across as rather cold on the screen, offers this film's warmest character.

At its heart, "The Arrival" is really just a contemporary take on those cheesy, B-level sci-fi thrillers that dominated the '50s. But it suffers from typical '90s movie problems - no logic, little character development and a thin story that is supposed to be compensated for by startling effects.

Instead, however, it's all silly paranoia and cheap thrills.

"The Arrival" is rated PG-13 for violence, profanity, vulgarity and nudity (Polo and Sheen discreetly shown together on a balcony, Sheen leaping out of a bathtub and a woman sitting on a toilet, screaming when the ceiling crashes in around her).