The New Mutants flew away from the destroyed site of their old school. Brightwind had survived the destruction and found Mirage. They weren't sure where to go, and when Wolfsbane suggested that they all call their respective parents to go home Warlock reminded her that he had no parents to return to. They were all exhausted, it had been at least two of three days since they last slept. So they landed in town to make a phone call, but a local woman called them demons and demanded that Wolfsbne hand over Illyana (a seemingly normal child) to her. Sunspot grew enraged at the accusation and powered up his crackling black fire effect to scare the local bigots away. Just as Mirage used her power to conjure up a quarter for the pay-phone, the police turned up chasing the New Mutants back into the air. Warlock then suggested that they return to X-Factor's Ship where their friends the X-Terminators lived.
The X-Terminators were swimming to the bottom of the ocean. Jean Grey had insisted that the X-Terminators have a lesson, and they had convinced Ship that an underwater excursion would be educational. So Ship created bubble-helmets, air tanks and flippers and they were enjoying their swim. Rictor disturbed an octopus, which shot ink at them. It also drew the attention of sharks, which Skids kept at bay with her deflector shield. Boom-Boom tried to use her time-bombs, but the water resistance meant that they floated too slowly. Rusty had to heat the water up to flush the bomb away from them and into the coral below. Rictor used his vibrations to stir up the water and confuse the sharks into leaving.
Free to swim in safety again, the X-Terminators made a discovery; a bizarrely shaped shell. Rusty picked up the shell and they swam back to Ship to investigate further. Boom-Boom was grossed out by the years worth of slime and coral that had grown over it, bit Rictor guessed that it was in fact an ancient Atlantean artefact. While the X-Terminators enjoyed eating burgers, Ship analysed the artefact and revealed that it was an ancient horn. Rictor, pleased that his theory was correct, used gentle vibrations to shake the ancient sea sludge off the horn. Each of them took turns to try to play the horn; Rictor, Skids and Rusty couldn't make a noise. However, when Boom-Boom tried her lungs blasted a huge note from the horn (and unclogged the shell that was jamming up the trumpet of the horn).
Immediately Ship began to tremble as mighty tentacles reached up from the ocean floor and wrapped themselves around Ship. The sea creature was dragging Ship underwater. The X-Terminators managed to pull on their scuba gear moments before they fell into the water. Their powers weren't enough to stop the monster, but at that moment the New Mutants arrived. Rusty climbed onto Brightwind behind Mirage, while the other X-Terminators were pulled out of the water by Warlock. Rusty aimed his fire down at the tentacles of the giant sea monster. However, Boom-Boom rationed that since the Atlantean horn had summoned the creature that another blast of it might drive it away.
Before she could put the horn to her lips, a man's hand wrenched it away from her. Namor appeared in the air before them and he was angry. he accused Boom-Boom of being mad for stealing the ancient relic and using it to summon monsters. Cannonball jumped to her defence and accused Namor of leaving dangerous artefacts lying around, since the X-Terminators had found it on the ocean floor. Rusty demanded that everyone calm down, since they needed to save Ship before they fight each other. Namor was impressed with Rusty's diplomatic manner and admitted that he had lost the horn during a fight many years ago (see Fantastic Four #4). Namor agreed to work with both young mutants teams to drive the monster away to make amends for losing the horn & therefore inadvertently causing their troubles.
As Namor wondered how the New Mutants would be able to breath underwater, Mirage used her power to summon up more scuba gear with an Atlantean twist. Warlock transformed into a submarine and they all dived into the water. Down in the waters they found a giant squid. Namor recalled how the Fantastic Four had defeated a similar monster with a bomb, so Boom-Boom created a time-bomb with a longer countdown. Rictor, Rusty and Namor kept fighting the monster while boom-Bomo counted down, but the monster rolled over at the last moment so the explosion made a minimal impact. Rictor recalled how his dad had worked with dynamite in South America, and explained that the bomb needed to be nearer the monster's brain. Mirage offered to conjure up some TNT, but that meant their scuba outfits would disappear. So everyone climbed in Warlock-the-submarine to plan their next move.
Mirage created the TNT and Boom-Boom crated time-bombs to act as a diversion, which Sunspot through with all his strength out of Warlock's torpedo shoots. However, the impact only made the monster angrier and it wrapped its tentacles around Warlock. Warlock began to leak water and the monster opened it's beak to eat them all. Cannonball then flew Rusty & Skids into the monster's mouth to lay the dynamite. Rusty managed to ignite the fuze underwater, while Skids' force field protected them from the blast.
Moments later they reached the surface, soon followed by Ship bobbing along. X-Factor arrived in a hovering shuttle and demanded to know why Ship was in the water, where the flying horse had come from and what was going on. Ship & Namor explained what had happened and Namor soon flew off with the monster-summoning horn. The X-Terminators then begged X-Factor to let the New Mutants stay with them on board Ship. X-Factor agreed, and Iceman explained that they knew what thad happened to the school as it used to be their home too.
X-Factor welcomed the New Mutants to live onboard Ship with them. Everyone was happy, but Wolfsbane wondered what they should do with little Illyana who was still powerless.