A sinister Digimon pirate named Mermaimon hatches a plan to release her fiance AncientVolcamon from the island Muranthias on Earth. To get to the island, she needs to kidnap a wizard Digimon named Hitazumon from the dimension Liaria, & use his magical key. Luckily for Hitazumon, he evades capture & flees to Earth, where he seeks protection from the DigiDestined.
The DigiDestined are practicing for a martial arts tournament. Cody makes a wrong move & ends up throwing out his back. While visiting him at the hospital, a young friend of the DigiDestined named Trevor discovers the DigiDestined's identity.
Seraphimon summons the DigiDestined to protect Hitazumon. Armed with Digi-Boxes, Alex & Mia rescue Hitazumon from the African wilderness, but they end up losing him to Mermaimon later on. Mermaimon takes the wizard Digimon to Muranthias along with other captives - Brick & Stick, Taylor, Maggie, & Hitazumon's wife & child.
Before taking off after Mermaimon, the DigiDestined are given new powers by Seraphimon & Kokuwamon, which makes them the Turbo DigiDestined. They are joined by Trevor, who takes Cody's place. The DigiDestined sail on a ship to Muranthias, where they face the Putramon. Mermaimon arrives on the island along with her crew - Boogeymon, DarkVolumon, & an army of MetalPiranimon - & sacrifices Taylor & Maggie to AncientVolcamon's fire.
The DigiDestined reach the temple to find their friends turned evil by AncientVolcamon's flames. The team battles Taylor, Maggie, & the rest of Mermaimon's forces as AncientVolcamon arises from the fiery pit. Hitazumon restores Taylor & Maggie, & the DigiDestined fight AncientVolcamon with their Digi-Weapons. The DigiDestined flees, & AncientVolcamon grows into a giant. The DigiDestined call on their Turbo Digimon & form TurboOmnimon, with which they destroy AncientVolcamon.
The DigiDestined save the world just in time to win the martial arts competition, as an infuriated Mermaimon swears vengeance on the heroes.