February 15, 1898 - Havana harbor - USS Maine (ACR-1)
Shortly before midnight, two midshipmen, Ben Finney and Matt Decker, are having an illicit smoke on the forward deck. They spot a strange glowing swirling in the water just off the bow. Thinking it was a group of phosphorescent jellyfish, they looked closely, and were shocked to discover three men fighting with long knives in the water, trying to drown each other. Two were human looking, but badly mis-shapen and non-symetrical. The last one, an older man with a very muscular build, also had some sort of heavy barreled rifle, like a long shotgun. He fired and missed, but the shot went right through the armored band of the ship. There was an explosion…
…and the two Earthmen slowly regained consciousness over a matter of weeks, losing almost all their memories in the process. They became Mat and Ben, pit fighters and slaves of Ciloon Kor, warlord of Barsoom.
Mat and Ben were put back together and indoctrinated by a First One scientist, the chief servant of Ciloon Kor. Their lives consisted of eating, sleeping, fighting savage beasts or prisoners of war in the arena pit, and healing up. Their past was forgotten, and they figured they were "synthetic men" created by the scientist, since it was mentioned a few times that he created such things.
One day, while fighting two Barsoomian "lions" (eight-legged fanged horrors far more fearsome than the Earthly version), one of the spectators leaned too far over into the pit and fell right into Ben's arms! This was Princess Darlah, sister of Ciloon Kor and only daughter of the high king Utan Kor the Conqueror! Mat and Ben succesfully rescued her, but at the price of both of them being mauled almost to death.
Only the weird science of their master's scientist saved them from doom. As they rested up in their cages, Princess Darlah came to them and set them free! Ignoring Mat and Ben's inappropriate suggestions, she recruited them to her cause. The high king was presumed dead … at least, he was gone … and she suspected one of her three brothers of being the culprit behind the assassination. For justice, honor, and revenge, she was determined to rally the Synthetic Men who lived outside the city in the nearby Valley of Doom, lead them back to the city, and force her brothers to reveal their guilt or prove their innocence. Mat and Ben weren't so sure about this "Valley of Doom" business.
The princess led them from their basement cage to one of the high spires towering above the city. At the top was an airship platform -- her plan was to steal a small ship and sail off to the lair of the synthetic men. The trio was intercepted by one of her brothers with a coterie of guards! Risking all, Mat tackled the warlord, sending them both down the stairwell. Ben and the princess pushed off in the air-boat, trying to find the level when Mat ended up. One of the guards jumped down onto the boat. Mat broke away from the warlord and jumped out the window, also landing on the boat! Ben managed to knock the guard off the deck, but on the way to his doom managed to grab Mat's ankles. Mat was now hanging onto the edge of the deck by his fingertips, while an enraged guard was trying to climb him! Also, the warlord had recovered and was trying to take potshots at the boat with a radium gun! Fortunately, Mat shook his opponent loose, and Ben maneuvered the craft away from the gun. They were free!
Several hours later, they reached the valley where the synthetic men dwelled. These were escaped slaves of Ciloon Kor, the same as themselves. They were wary of Mat and Ben, not accepting them as synthetic men, since they were mis-shapen, asymetrical versions of Red Martians, and Mat and Ben, being Earthmen in reality, didn't really look like them at all. The leader challenged Mat to a bare-handed fight, and beat Mat into unconsciousness, but he put up enough of a struggle to convince them of their honor and sincerity. They agreed to aid the princess in her struggle.
The synthetic men, Mat and Ben among them, stormed the city! Mat and Ben found the laboratory of the First One scientist, who was firing up the Lok Nar, which created gates between worlds. They dispatched the mad scientist, but the golden radiation enveloped them and they found themselves in Cuba during the Spanish-American War, their memories restored. They found glory in that war, but nothing to compare with their adventure on Barsoom.