A civilian oil rig crew is recruited to conduct a search and rescue effort when a nuclear submarine mysteriously sinks. One diver soon finds himself on a spectacular odyssey 25,000 feet below the ocean's surface where he confronts a mysterious force that has the power to change the world or destroy it.

A ship sent to investigate a wave of mysterious sinkings encounters the advanced submarine, the Nautilus, commanded by Captain Nemo.

The wealthy and impulsive Rollo Treadway decides to propose to his beautiful socialite neighbor, Betsy O'Brien. Although Betsy turns Rollo down, he still opts to go on the cruise that he intended as their honeymoon. When circumstances find both Rollo and Betsy on the wrong ship, they end up having adventures on the high seas.

This is an Australian made-for-television animated film from Burbank Films Australia. The film is an adaptation on Jules Verne's classic French novel, Twenty Thousand Leagues Under the Sea (1870).