The prehistoric ancestors of great white sharks have been lured from the deep trenches where they have survived for millennia. At a Mexican resort, a water patrolman finds a shark tooth on a dive. He tries to figure what type of shark it is from but cannot find a similar tooth on the Web. He then posts a query with a phot of the tooth.

Well, the tooth belongs to a megalodon, the ancestor of the great white, which can reach lengths of 70 feet or more. A paleontologist sees the post and travels to Mexico to prove some of her theories, but she keeps the nature of the shark a secret from the locals.

But soon there are some attacks and it becomes known that the shark is there. It is a 15-foot baby. It seems to be attracted by an underwater fiber-optic cable that has a major junction just off the coast.

Our heroes set of to catch or kill the shark. It looks like they are successful when suddenly an adult shows up in a dramatic scene.

Now the hunt really begins. We have paleontologists, divers, hotel owners and communications conglomerates all coming together for the final quarter of the film.

No one built a 70-foot robot shark for this movie. Instead, creative use of camera angles gives a sense of massiveness to the shark footage. Very well done with a relatively small budget, but without the small-budget feel.

This movie seems to be a retelling of the book Extinct by Charles Wilson, but I could find no mention of it.

If you like shark movies, then you will probably like this one.