The plot of the fourth game - which, judging by the presence of someone named Aline, is the "basis" for the film - is like this:
Edward Carnby is investigating the disappearance of some people in this family's mansion on a secluded island. Aline Cedrac is going to the same island because one of the members of the family is an expert on a native American tribe she's interested in, but also because she thinks he might be her father. For some reason, they team up, but the plane they're on is attacked by a monster en route to the island, and they must parachute down to the island. Aline lands on the roof, Edward in the forest outside the grounds.
The player can take control of either character - occasionally cutscenes will be triggered in which the other character contacts the one you're playing on their walkie-talkies, often offering some piece of information which might be relevant later.
Edward runs into some government agent who's been attacked, and must make his way through the monster-infested gardens into the manor. He's armed, and his half of the game is a bit more action-oriented, though still in the survival horror for-God's-sake-don't-waste-your-ammo sense. Aline, upon entering the house through a window, encounters the mother of the two brothers who own the house, blind and bedridden, who tells her that light repels and even destroys the monsters infesting the house - accordingly, for a long time Aline defends herself with a torch that keeps the stronger monsters at bay.
As the characters explore the house, they piece together a convoluted family history involving experiments with Lovecraftian powers which also have something to do with the religion of the original native Americans who inhabited the area. Frankenstein-esque experiments and the like attack the heroes, and lots of generally weird
goes on until both Aline and Edward end up in an alternate dimension, chasing after the brothers and trying to close the portal between the worlds with ancient native artifacts.
