Chaperoned by Ororo, all of the Institute’s students, except for Rogue, are taking a cruise. While the rest are having fun, Amara doesn’t feel well being out at sea. Scott and Jean are enjoying their alone time together as a new couple.
Jean: “Ah, isn’t it beautiful Scott? I’ve never seen so many stars.”
Scott: “Yeah, you don’t get nights this clear back in Bayville.”
Jean: “It’s just so peaceful. Out in the middle of the ocean, just floating, and no one knows we’re mutants, no one’s calling us names, no nasty looks...”
Scott: “But, the best part is, you and I finally get some personal time.”
Scott and Jean embrace and are about to lock lips when Kitty and Kurt’s snickers give their hiding place away. Annoyed, Scott and Jean leave in search of another quiet spot. That is when they notice ice sculptures floating in the ocean, courtesy of Bobby.
At the bow of the cruise ship, Bobby is creating ice sculptures to impress Tabitha and namely, Amara. Bobby goes overboard, literally, after recreating the tip of the iceberg that sank the Titanic in the movie when he is caught in action by Scott and Jean. Jean rescues Bobby with her telekinesis. Amara finds out that she can’t summon her powers to melt the ice. Scott steps in and blasts it into smithereens. After exchanging a few angry words with Bobby about “drawing attention to [them]selves”, Scott storms off.
The next morning, Amara still isn’t feeling herself, citing that she doesn’t “do well when [she]’s been away from the ground too long”. She passes on breakfast and Ororo comes to check in on her just as Tabitha leaves for the dining cabin. Bobby cautions Jamie on using his powers after getting on Scott’s bad side the previous night.
Scott and Jean are seated by themselves in a private corner. Kitty and Kurt scrutinize their lovey-dovey acts as Scott offers Jean a rose from the table’s vase. Kurt imitates Scott by offering a croissant as “a symbol of [his] love” to Kitty, who imitates a gushing Jean.
Meanwhile, Tabitha has had enough of the whining lady seated behind her. She tosses one of her little exploding balls onto the lady’s plate, blasting breakfast into her face. The lady jumps from her seat, knocks into a waiter carrying a flaming plate, which lands on a table and sets fire to it. All the people panic and scatter. Jean is the first to react and floats the aquarium over to the fire with the intention of putting it out. She is then distracted by the whining lady calling her a mutant, and another knocks her over, causing Jean to tip the aquarium over too much, pouring the live lobsters out with the water. The students try to catch the lobsters, and in doing so, Kurt’s holowatch gets short-circuited, exposing him and the rest as mutants.
All of a sudden, the entire cruise ship is hostile towards them and the name-calling begins. On deck, Bobby lowers the temperature in the pool as payback. Scott and Jean make their way to one of the quieter decks on the ship, assuming they’ll be docking in the Bahamas soon. At that time, the captain announces that there’s “rough weather ahead” and they’ll anchor off St. Sebastian Island to wait the storm out. Amara is horrified at the news, desperately needing to “get to shore”.
Scott isn’t taking to the hostility any better. In a bid to cheer him up, Jean hatches a plot to get him off the ship and fly them over to the island in the distance for a bit. Kitty and Kurt catch them “flying the coop”. Kurt teleports them both to shore. Meanwhile, Tabitha is planning on getting Amara to dry land and finds just the right tool: Bobby.
Scott and Jean are just beginning to enjoy themselves in the marketplace when they spot Bobby, Tabitha and Amara; just the “X-kids” they were trying to get away from. Bobby explains that they needed to get Amara on shore “before she freaked out”. They suggest a trip to the hot springs. Scott is not interested, but points out Kitty and Kurt, to get the two “stalkers” off his and Jean’s back.
At the hot springs, Bobby refuses to get into the hot water. Amara is instantly revitalized. She swims down to a fissure and unknowingly triggers an earthquake when she transforms into her flaming Magma form. The hot spring begins to boil. Kitty, Kurt and Tabitha leap out of the the water. Amara rises from the water, calling out to them to leave immediately. Bobby ices a bobsled as a means of escape.
The marketplace experiences the earthquake as well. Buildings and power lines collapse. Scott and Jean use their powers to stop a rockslide. The rest of the students arrive and rescue the villagers with their powers. They are celebrated as heroes instead of being feared. They spend the rest of the afternoon enjoying the good life.
In the evening, the heroes are celebrated with a feast. Amara confesses to Scott that she thinks she might have caused the volcano to “awaken” when she came into contact with the fissure at the hot springs. When Ororo finds her students gone, she begins to suspect they’ve gone off the ship without permission. The escapees find that out when they see an angry thundercloud forming over the cruise ship. At the same time, the volcano makes a timely explosion.
The villagers run for cover. While the rest of the students try to stop the lava flow and rescue some stranded natives, Amara finally understands the true nature of her powers and scales the volcano. Storm flies over to the island, creating a storm on the way to extinguish the fires. She then goes after Amara, who jumps into the volcano when she discovers she is the key to stopping it. The lava hardens and stops flowing, and Amara escapes, unscathed.
When they return, the villagers are still cheering them on while cleaning up the messes. Even Storm is impressed by the hospitality. Even so, a punishment is still in order when the students return to the ship, in whatever way they got onto the island.