Uncanny X-Men #25

Professor Xavier and the rest of the X-Men are driving Jean Grey back to Metro College after a visit. Along the way, they come across an orphanage that has caught fire. Changing into their X-Men costumes, the mutant heroes work together to save the orphans within from the flames before fire crews can arrive on the scene. With everyone safe and fire fighters putting out the blaze, everyone tries to thank the X-Men for their help but the heroes have disappeared as quickly as they appeared. When they arrive at Metro College, both Scott and Warren take note of Jean's classmate, Ted Roberts, and how he has an obvious interest in her. Scott deals with the idea of trying to get over her while Warren has decided to seek romance elsewhere.

Far away in Central America, a man known as El Tigre leads some men to try and find the hidden pyramid of the Maya god Kukulcán. His guides, two mercenaries named Toloc and Ramon, make no attempt to hide their contempt toward their employer. After digging up the ground near the pyramid for hours, they finally uncover a stone chamber that holds the sacred gold of Kukulcán, a lost treasure that is said to be cursed. While inspecting the golden relics, El Tigre notices a glowing stone that falls out of a goblet. Unaware that it is the Sacred Pendant of Kukulcán and unable to identify the substance from which it was carved, El Tigre stows it in his shirt pocket so he can examine later. That night, as El Tigre sleeps, Toloc and Ramon initially plan to kill him but then decide to instead tie him up so they can force him to help them unearth the rest of the gold before they kill him. However, having been warned by a sixth sense, El Tigre is feigning sleep and he surprises them and himself when his spoken desire that they be entangled by their own ropes comes true as the ropes wind around the two men. With the two would-be killers now bound, El Tigre has them swear their loyalty to him or face death by machete. Later, while stoking the flames of their camp fire, the stone falls out of his pocket, as if it moved of its own accord. When he picks up the pulsating stone, El Tigre discovers that he can now read the Mayan hieroglyphs inscribed on the base of the pyramid. From the inscription, El Tigre learns the story of the Sacred Pendant of Kukulcán and that the part of that enchanted amulet carved from a magic stone that he is holding is the source of his new-found mental powers. When he further reads that whoever possesses both halves of the pendant will enjoy power without limit if he survives its dread curse, the power-hungry El Tigre decides that the full might of the god Kukulcán must be his, curse or no curse, and that nothing will stop him from finding the other half of the pendant.

A few days later in the United States, the X-Men are studying when suddenly the Cerebro alarm goes off, prompting the group to investigate. The Professor decides to go downstairs by using his leg braces, but their power supply fails. He is rescued from a bad fall by special metal tentacles that he had installed into the wall to prevent such an injury. Returned to his wheelchair, the Professor and the X-Men check Cerebro and learn of the coming of a powerful force, which may or may not be a mutant, but which is arriving in New York City.

Cyclops, Beast, Angel, and Iceman then travel to the city to investigate further, as El Tigre and his men are arriving in New York. El Tigre uses his amazing mental powers to compel a cab driver to take them to a nice hotel. As they are being dropped off, Scott spots them and gets a feeling of impending danger from the strangely-garbed men but dismisses the feeling, thinking that he's sounding like a third-rate fortune teller. When Scott returns to the X-Men's hotel room, he learns that the rest of the team was just as fruitless as he was in finding the source of Cerebro's alarm. Deciding to check the newspapers, Scott goes back outside but, while reading and walking, he accidentally bumps into someone which causes his glasses to be knocked askew. Quickly getting his optic blasts under control, Scott has to flee from a group of mutant-haters.

Returning to the hotel room, Scott arrives just in time to watch a TV news report about a strange brawl that broke out in a nearby restaurant. When the report shows as photo three individuals who did not participate in the brawl, Scott recognizes them as the men he saw earlier. Confirming Scott's suspicions that El Tigre is responsible, the Professor transmits instructions via telepathy to his charges on how to deal with the threat. He explains that he had been using his mental powers to track El Tigre and his minions after they left the hotel, fleeing ahead of the police who had tracked them back to their hotel. However, once El Tigre had arrived at the City Museum, he had suddenly detected the Professor's probes and blocked him from monitoring his actions any further. Despite this, the Professor still knows his location and he sends the X-Men there in uniform to confront El Tigre.

The X-Men arrive at the City Museum where they decide to split up and search for El Tigre and his men individually. The Beast runs afoul of animated suits of armor until he is caught up in one of Ramon's bolos and is knocked out. Iceman, while searching an arctic exhibit, is similarly tripped up by rope that is tied across a staircase and crashes into a brick wall. In a prehistoric exhibit, Angel is also downed when he is struck by a blow dart fired by Toloc.

Meanwhile, Cyclops has followed a hunch and gone to the Pre-Colombian wing where he soon spots El Tigre. However, before he can stop the crook, they are both surprised by one of the museum's security guards. El Tigre instantly uses his mental powers to command the guard to keep Cyclops at gunpoint until El Tigre can retrieve the missing half of the pendant. Finding it in a display case, El Tigre smashes through the glass, liberating the fragment he has sought out. Joining the two halves together, El Tigre is suddenly enveloped in a bright flash of light. When the light fades, he is El Tigre no more, as he is now garbed in ancient clothing. He announces that he is now the reincarnation of the Mayan god Kukulcán!