Hell, or Tidewater is set in a not-too-distant future where the world has come to a crisis point with regards to the environment. The Canadian government has approved the construction of a massive pipeline that will run through the underwater bridges of Tidewater, a place that has been long considered sacred by the indigenous people. However, there is a group of activists that is opposed to the project and is determined to do everything in their power to stop it from going ahead.
As the construction of the pipeline begins, Lt. Cmdr. Allan Parker is sent in by the government to oversee the project. He is a seasoned Sea Dog, with many years of experience in underwater submarine action. However, he also has a chip on his shoulder and is resentful of being sent to Tidewater. Parker soon discovers that the pipeline construction is not going as smoothly as the government had hoped, and there are many unforeseen problems that arise.
As Parker starts investigating the reasons behind the glitches, he realizes that there is an unknown enemy lurking in the depths of the water. The crew on board the submarine starts experiencing strange and deadly incidents that are beyond their understanding. Parker soon uncovers a sinister conspiracy behind the pipeline project, and discovers that there is a group of rogue scientists who have been experimenting with genetic modification in the undersea labs.
The tension in the film peaks as Parker and his crew are trapped in a deadly game of cat and mouse with the rogue scientists. The underwater submarine action scenes are captivating, and the environmental theme of the movie is timely. Hell, or Tidewater is a nail-biting thriller that keeps you on edge until the very end.