I paid $2 for my DVD of this low budget horror film from the UK. I'm not sure I got my money's worth.
Grim is a derivative and inept monster movie, with a slim plot, bland characters, and very little in the way of either tension or action. What it does have plenty of is "stupidity". Right from the start it kicks us off with ouija board action. You know, the board game produced by Hasbro. Summoning any genuine supernatural force with one of those is a bit like starting WW3 by playing a game of Risk.
Nonetheless, in the world of this movie, ouija boards can waken a vicious troll from its eternal slumber, and said troll can then run around killing and eating people. Except, you know, for the random scantily clad woman that it abducts and keeps chained up for no apparent purpose (at least, thank goodness, no purpose shown on screen).
Like all sane persons, what the characters in this film do when confronted by a series of murders is to go spelunking. Because there have also been strange subsidences in the ground and obviously these things are connected. Seriously, I know movie characters are usually hopeless at making connections between obviously related things, but there's such a thing as going too far in the opposite direction.
Now to be fair, some of the folks on the caving party were involved in accidentally summoning the creature and so know it is there and want to either banish or control it, depending on their individual personalities. But every other character who goes along must've just read the script or something.
So they wander around the caves for a long time, bickering with each other, until they start being picked off by the troll. I don't remember exactly what the timer count was up to by the time they started dying, but I wish it was earlier. Eventually the obvious survivor characters work out the creature's weakness and defeat it.
This is a very poor film, with the only entertainment being just how badly staged, edited and acted some of the scenes in it are. There are much better schlockly films out there: watch them instead.