In the near future, the polar icecaps have melted, the coastal lands have flooded, and billions have died. Mutant man/animals have risen up against humanity, which is fighting just to stay alive. This is all the work of one man, Professor Zorndyke, a genius gone mad who for unknown reasons has caused so much devastation. In the middle of all of this is the submarine "Blue Submarine No. 6", of the Pacific Blue Fleet, and her crew. They and what's left of the navies of the world are on a last effort to defeat Zorndyke and his aquatic armies.

Blue Submarine No. 6 stands out among OAVs in several ways. The fist, and most obvious difference between Blue Sub 6 and other anime is the extensive use of 3D computer animation. While this is done in other anime, a very large portion, including every vehicle combat scene, is done in CG. At times it can be a little disorienting switching between flat, 2D animation and 3D graphics, but it doesn't take long to get used to it. Zorndyke's mutant armies stand out as well, ranging from mutant animals, to combat whales, to new races of mer folk. Zorndyke himself has a pretty strong Dr. Moreau complex, complete with tropical village of beast-people. Zorndyke's character is is creepy, with a calm even voice that makes him sound completely insane. He also looks a little like Bill Gates, which is even creepier.

Blue Sub 6 has plenty of action, great visuals and sound, with a complex story. On the downside, the story may be a little too complex for an OAV, it would have done better with 6 rather than 4 episodes. Some of the character motivations are left unclear, and the story seems a little too compressed. Also, expect to shell out a lot of money for this OAV, each episode is released as a separate DVD. There is also an edited movie version available, that was shown on Cartoon Network. It might be your best bet, as far as affordability goes.