I don't like it when they turn a book into a movie and I've already read the book: the films never usually do the story justice. Phantoms, a 1984 novel by Dean Koontz, is the subject in question here, and the screenplay is done by Koontz himself.
As with any novel, there are subplots and sequences which just are too complicated to be put in a 2 hour movie, or will not translate on screen. Koontz does a good job of weeding out the fat and just keeping the meat there.
The film begins with Dr. Jennifer Pailey bringing her sister, Lisa, back home with her to the small town of Snowfield, California, only to find the town desterted, and a handful of its residents dead in their houses. Joined by the sheriff and his deputies from a close-by town, the small group soon find themselves terrorized by a creature who is everywhere and nowhere at once. A clue connects to creature to tabloid journalist, Timothy Flyte, who has been studying the phenomenon of mass disappearances throughout history for years. A military team of scientists and soldiers, joined by the doctor, work with the Sheriff and Pailey sisters (the two deputies having been killed by the monster) only to be picked off one by one by the shape-shifting presence.
We soon learn that the creature has been around for millenias and has become sentient (absorbing the thoughts and knowledge of those it consumes), as well as developing a devil complex (similar to a god complex, only on the other side of the book). It wants Flyte to chronicle its history, and tell the world it's there. But it believes itself invincible and it doesn't take the Sheriff and crew to figure out how to stop it.
Sort of like an Andromeda Strain meets the Blob, Phantoms begins at a choppy pace, moving to quickly for its own good, but soon settles into a smooth rhythm of death, terror, and excitement. The actors include a fine assortment of rising stars, including Ben Affleck, Rose McGowan, and Liev Schreiber (in a wonderfully creepy performance), as well as the veteran Peter O'Toole who holds it all together. Director Joe Chappelle, having had experience in mostly the horror genre, shows that he's honed his craft, and proves he can do much more with some utterly beautiful shots throughout the film.
The film will likely remind you of '97's Mimic, but it's so much better.