Sixth graders on a field trip accidentally become the crew of the Disco, Very!, a submarine set to explore the Bermuda Triangle.
Mac Wynne and Amir Abdellah are best friends riding on the bus during a school trip to the aquarium. Also, on the bus are best friends Patty Bethany Wei and Maria Sanchez. Due to an incident, all four children are separated and rearranged by their teacher, Mr. Moore and are forced to spend the rest of the day together.
After not getting along at first, Amir helps Patty with her octopus fighting video and Mac connects with Maria through drawing.
Finally, the four find each other in the aquarium and can’t help but reunite. After seeing Mr. Moore and fearing the trouble they’ll be in, the four escape into a faded pink submarine with the word Discovery painted across its side.
Mac accidentally closes the hatch of the submarine and locks everyone inside. After exploring the submarine more, the four encounter a short, old man, Captain Slipington Narwhal Slide, the captain of the submarine along with his crew, first mate Maurice the monkey and communications officer, Natasha the French parrot.
Captain Slip tells the four that they are his new crew much to their disagreement. He also tells them that the Submarine is called, the Disco, Very! Also, to the four’s disagreement, but Captain Slip justifies the name by striking a button and causing the room to fill up with lights, music, and a disco ball. Captain Slip also explains that the Disco, Very! is set on a voyage for the Bermuda triangle to capture the dreaded Nonapuss, of which Captain slip owns a severed tentacle.
The children continue to believe the submarine is an odd aquarium attraction until they look through the periscope and see the ultraviolet horizon of the Bermuda Triangle coming toward them underwater.
Captain Slip explains the submarine has been moving since the hatch was closed. The children explain they can’t just be kidnapped, and people will miss them. But Captain Slip says, “And I know you'll be missing your beloved parrots and monkeys back home, but they won't be missing you. Time doesn't exist inside the triangle. I'll have you back on your field trip eating lunch before Mr. Moore knows you were gone and spending time together.
Captain Slip falls asleep before he must explain anymore. Without any other choice, Mac, Amir, Patty, and Maria begin to do the jobs of a submarine crew. Captain Slip secretly implies that this is how he gets all his crew as the submarine enters the Bermuda Triangle and disappears.