Xavier takes the X-Men on a vacation to South Florida (courtesy of beachfront property of Warren’s family), and en route to visit an old friend from college, Dr Connors.
At the house of Dr Connors, something has gone awry. Mrs Connors informs Xavier that her husband has gone missing. Using his research from the lizard’s regenerative abilities, Dr Connors extracted that gene and applied it to the human body, and successfully regrown the arm he lost to a “land mine” accident. But the side effect of the experiment (merging human DNA with lizard DNA) has mutated Dr Connors into a lizard, requiring constant doses of a serum. He had gone missing since his last transformation.
Xavier has Mrs Connors and her son relocated to her sister’s house while the X-Men search for Dr Connors. Hank, Warren and Scott immediately jump into volunteering for the search. Xavier decides he can manage with the help of Hank and Warren and orders Scott, Jean and Bobby to go to “Worthington House”.
The next morning Beast and Angel head out into the Everglades while Scott, Jean and Bobby hit the private beach after exploring the house.
As they drift deeper into the swamp, Beast starts giving Angel an impromptu lecture on the Everglades ecosystem. While examining the large alligators floating in the swamp, Beast suddenly finds Angel missing from the boat.
Meanwhile, Scott, Jean and Bobby are having the time of their lives on the beach. After some fun in the sun, Xavier telepathically informs Bobby to take shelter from the sun as “[his] physiology leaves [him] particularly vulnerable to sunburn”. With Bobby out of the picture, Xavier sets Scott and Jean up for some time alone, and telepathically nudges Scott to make his move.
Back in the swamp, Angel is attacked underwater by Connors. Beast dives into help Angel, but is overpowered by Connors. With some team effort, they manage to evade Connors and climb back into the boat. Angel suggests they head for land as the water is too dangerous.
Scott and Jean are fooling around in the ocean when Scott’s glasses slip and he lets loose an optic blast. Just when he was having fun he reverts back to his worrisome self. Jean urges Scott to let loose as there is no one that he can harm in the vast, empty ocean.
Even after heading for land, Beast and Angel are being chased by Connors. For a moment they manage to shake him off as Angel flings Connors back into the water. He returns to Beast with the end of Connors’ bitten off lizard tail.
Scott and Jean return from the beach in time to catch Bobby leaving in a hurry. Xavier had called for Bobby’s help to deal with Dr Connors. Scott is once again disappointed that he isn’t needed on the mission but Jean sees the upside of everyone’s departure.
Using Connors’ own blood from the tail, Beast intends to lure Connors out of the swamp and back into the house. The plan worked and as they approach the house, Xavier has Bobby waiting on the pier to freeze Connors in place so Beast can administer the serum.
Dr Connors transforms back into his own human self. Xavier reassures him that his family is safe. Xavier invites Connors over to Worthington House to explain what happened in “a more relaxing environment”.