In 100 Million BC we meet Dr. Frank Reno, a brilliant scientist who many years ago as a young man took part in a failed wormhole experiment, or as it can also be referred to - The Philadelphia Experiment.
Over the past 60 years or so, Frank has been feeling real guilty because he sent a team of soldiers to the Cretaceous Period with no chance of rescue. Luck finally comes his way as some scientist discover in some ancient caves writings that say "FRANK, IT WASN'T YOUR FAULT". This proves to Frank that the soldiers survived. Erik, his older brother had been one of the ones stranded in the past as well as a pretty nurse he'd had a thing for.
Frank decides to try to go through the worm hole again with a group of 2008 Navy Seal team. They are going to go to a time that is 6 years after that 1940's team arrived there. They take their trip and when they arrive in 100,000,000 BC they are welcomed by acid-spitting plants, dinocrocs, pterodactyls, and raptors. Much of the team gets killed, many used as munchies for dinosaurs. Frank and his surviving crew end up running into his brother Erik and the nurse he had a thing with and a few others. Frank also finds out that most of his original 1940's team are dead. This pretty much summarizes the first half of the movie.
The second half is mostly made up of a T-Rex running around loose in Downtown Los Angeles. When Frank rescued his brother and everyone got sent back to 2008, the current year. The T-Rex (known as Big Red) accidentally went through the wormhole. A lot of chasing and running around LA to trap the big monster follows!
Clearly 100 Million BC was a B-movie and despite the slam that many critics have given it, it really wasn't that bad to me. I mean, I know we can all make fun of the cheap dinosaur animation but it was way better than Land of the Lost wasn't it. OK, I know, for 2008 the animation it sucked. I'll put it this way though, the movie kept me entertained. It's a great movie to watch on a Sunday afternoon when you don't have anything else to do.