The plot is as simple as you can get, as is to be expected. Some company is drilling in a lake and accidentally comes across an underwater cave, unleashing a prehistoric Megalodon. That's right, an enormous prehistoric shark was living in a cave at the bottom of a lake. A couple of police officers getting into some extra curricular activities with some trashy looking ladies get eaten, an investigation ensues, more people get eaten. Then, from out of nowhere, the shark starts flying. Yes, flying. Through the air. Some sort of mad scientist comes into play, and a college professor (who has flashbacks to her sister dying in the same lake) has to put a stop to the Megalodon's reign of terror.
If the above paragraph didn't totally sell you on Raiders of the Lost Shark, then this movie simply isn't for you, and feel free to kindly move along. For those still with me, this movie is an absolute blast. It's awful, but in all the right ways. The acting is bad, but the script is written in a manner that the cast almost seems to be making fun of themselves before the viewer can. Case in point, the Captain that takes the professor and students out on the lake to search for the shark is obviously the "Quint" of the movie, but he also just so happens to have just a slight pirate accent to go along with his over the top performance. These movies are often of the make it or break it variety when it comes to the animal in question, and to be honest when I first put the disc in, I fully expected first person camera shots (ala Jaws) and maybe some stock nature footage from Shark Week cut into the movie. So you can imagine my surprise when a fully CGI shark leapt out of the water, growling, and snapped up another trashy young lady who was doing a photo shoot in the water. It wasn't a particularly good looking CGI shark, and they probably blew most of their budget on the two or three scenes where the CG was used, but it was there and that was something I never expected.
For killer animal purists, Raiders of the Lost Shark is probably a pass. It lacks the seriousness of even the typical SyFy fare, which itself is often not really serious. I wouldn't go so far as to call Raiders of the Lost Shark a spoof myself, but I can see where one could make that argument. If you have the ability to just sit back for an hour and some change, get some friends together, partake of some sort of mind altering substance, and just enjoy yourself though, there's a good time here. I dare anybody to watch the part were the shark just starts flying around for no discernible reason and not laugh. It simply is not possible.