After a close call with an apartment fire and a police standoff, Mr. Incredible and Frozone make it back home and back to their lives. The next day, Bob is fired from work after injuring his boss in an act of rage. At home, he discovers a secret message from Mirage, a secret agent who offers him real hero work on a remote island to stop the rogue Omnidroid 8000 robot. Bob heads off after giving his family the pretense he is still employed and is going on a business trip. After a vicious battle, he succeeds in his mission by tricking the Omnidroid into ripping out its own brainpan. Some time later, Bob is again summoned to the island where he ends up getting overpowered by the new Omnidroid v.X9 and encounters Buddy Pine who, embittered by Bob's constant rejection of him, has reshaped himself into a wealthy weapons designer and supervillain called Syndrome. Bob escapes and dupes Syndrome into thinking he is dead, and later learns that Syndrome used previous prototype versions of the Omnidroid to kill other Supers. Unfortunately, his wife Helen activates a homing beacon on Bob's suit to find out where he is, alerting Syndrome as the automated defenses incapacitate him.
Helen flies to the island on a private plane, finding that her kids Violet and Dash Parr had stowed aboard. Syndrome detects her approach and orders missiles to fire at the plane, presuming it to be the military. However, the Parrs survive and make it to the island. Helen infiltrates the base while the kids stay in the cave, which is actually an exhaust tunnel for the rocket to launch the Omnidroid 10000.
Next day, a perimeter alarm alerts security to the kids' position, forcing them to outrun Syndrome's henchmen. They meet up with their parents to fight against the henchmen only to be incapacitated by Syndrome's zero-point energy gauntlets and then re-imprisoned. Syndrome then sets off for Metroville to "stop" the Omnidroid while the rest of his henchmen watch on television. But the Incredibles escape and use another rocket to get to Metroville, with Mirage's help.
Syndrome's base is well organized and retro-futuristic in a 60's James Bond style. The main hanger is filled with jets and a few rockets. A lot of the hideout is apparently located underground. Some features inside the hideout include a dining area located in front of a waterfall made of lava that can disappear at will, a computer room that has the database for Operation Kronos within a hallway lined with booby traps that can fire expanding balls of black goo at intruders who wander into this room, a volcanic pit where Omnidroid 08 was fought, a cave containing the skeletal remains of various superheroes killed by the Omnidroids including Gazerbeam, an elaborate monorail system, and a volcanic crater that is used as a launch tower for the rockets carrying the Omnidroids.
It is implied the island's airport strip's direction is 26-08 (78 degrees northeast), according to the manta plane's announcements.
To keep Supers under surveillance while they were trying to stop the Omnidroid, a number of robotic bird cameras are placed throughout the island. Whenever it encounters a person, it will ask him/her the identification. If they don't answer in time, an alarm will sound.
Since the end of The Incredibles, Pixar released a fictional video, stating that the island was going to be converted into an island resort. The new developments on the island would include a shooting range, a defense academy, luxury accommodations, island dining, a spa and a headquarters for the world heroes. It was also shown that the Omnidroids would be used for things such as giving massages.
- The name is a play on the English phrase "no man is an island." It could also be a play on "No man's land," given the hostile environment and enemies there that are capable of killing superheroes.
- The island looks very much like Never Land from Disney's Peter Pan, and its more recent versions.
- Pixar has released a fake ad saying that the Vanquished Villains Redevelopment program is turning Nomanisan Island into a resort.
- A113 is referenced twice here: the first time as the conference room Mr. Incredible will have his meeting with Mirage there, and again as the prison cell Mr. Incredible will be locked in by Syndrome.
- The island appears to be located in the South Pacific Ocean, located where Rapa Nui (Easter Island) is in real life, according to E's GPS and the Moai Bob Parr used to prop open the lava curtain leading to the Omnidroid's computer control room.