MAI Tech was an technology company that received its name from its founder, Marcus A. Irving. It produced several lines of robots and holograms, and in an alternate timeline, it produced android duplicates of people.
By 2038, MAI Tech had purchased the land that housed Lone Pine Ranch in 1955, Lone Pine Mall in 1985, and Lone Pine Fli-Drome in 2035. The building was redesigned as the Lone Pine Adventure Center. MAI Tech had placed robots and holograms in different rooms in the adventure center, intending each to portray fantasy versions of different eras of history.
In 1893, for the maiden voyage of the Time Train, Dr. Emmett Brown took his family to 2038 to visit the part of the adventure center that was designed to resemble a 19th century view of the future. He had hoped that this would provide a controlled environment for his sons, Jules and Verne, to explore the future. The center proved to not be as controlled as he thought. His sons mistook one of the robots displaying a hologram of an X-ray for a robber, and tried to apprehend it. They ended up causing the robot, and several others, to malfunction. Doc decided that the boys needed an even more secure environment. However, Clara suggests that they run their errand before deciding on a destination. They travel to October 1985 to reunite with Marty and Jennifer.
In 1986, Marcus Irving stole Doc Brown's flux capacitor to complete his Yugo time machine. He stole technology from as far ahead as 2008 and brought them back to 1997. He founded MAI Tech, and manufactured and sold the technology as his own. He also designed several androids, designed to look like Marty and Doc, using photographs he downloaded from the internet.
Marty was captured by these doppelgangers, but Emmett Brown managed to escape. He could still fly the DeLorean, as the flying circuits were untouched as Marcus was unaware of them. A doppelganger of Marty was outside the car, and Doc let him in. However, after he accidentally off the face, he realized that it was an android, rather than a person from an alternate timeline as he and Marty had originally assumed. He knocked the android out the window and went back to rescue Marty, who had been taken to Marcus Irving's hideout.
Doc used the technology from the android to trace the other androids, and discovers Marcus Irving's hideout and told Marty that the situation was not as it appeared. Doc incapacitated the other robots with the electric gun that Griff Tannen had used on him in 2035.
Marty and Doc then went to find the remaining android before it could do any harm, but they were too late. The faceless android knocked out Needles' gang with a knock out serum mixed with a memory clouding agent that made their memory hazy. It was doing the same to Needles himself, when Marty showed up to stop it.
Doc meanwhile, headed to the DeLorean, and found that Irving had repaired it, placing the flux capacitor back in place and replacing the tires. Doc tried to use a remote control override, when the aged Marcus Irving used the knock out serum on him.
The android took the DeLorean to 1997, and the Yugo time machine took Doc, Marty and Marcus to 19654 B.C.. Marcus initially planned to strand them there, but Doc's warning about a butterfly effect changed his mind. One of the Marty androids disinfected a scratch that the real Marty had received from a sabre-tooth tiger, then they all headed back to 1997.
In 1997, Marcus took Doc and Marty through his lab, and they saw the technology that he has collected. Doc realizes that the technology is from the 21st century, and Marty realizes that he is pulling a "reverse Biff", going into the future to make himself rich.
Marcus locked Doc and Marty in a room with his androids, telling them that he didn't mind if they were killed in this time period. Doc used the second DeLorean time machine's remote control override, causing the DeLorean to drive over an android, out of the garage, and up to the penthouse level, where Doc and Marty are being kept, crashing through the window.
The elevator Marcus was on automatically took Marcus down to the garage level, while Marcus was pushing the button trying to get it to go up. Doc and Marty got into the DeLorean and flew down to the garage. Doc explained that they couldn't just go back and stop Marcus from taking the flux capacitor, since the effects on a time traveler aren't instant, pointing out that it took a week for Marty to begin to fade from existence in 1955. Marcus and Doc could get in a reverse time race, with each vehicle going further back in time to try to prevent the other from making changes.
Marty saw a photo album and realized that Marcus had been alone all this time. A female android that was built to be Marcus Irving's sister comes online, and Doc and Marty realized that Marcus had become a bit crazy during his decade of living all alone. Marty realized that his fear of being all alone is what drove him to find Marty in the first place. They decided to take Marcus to his younger self, traveling in the DeLorean back to 1986.
The DeLorean arrived in 1986 just as the younger Irving was driving away with the stolen flux capacitor. The older Yugo time machine arrived shortly afterward. The younger Irving was pleased to see his older self at first, until he realized how foreboding he had become.
The older Irving sent out the androids to kill Marty and Doc, as well as everyone else in the way. Irving at first thought that his story about multiple universes was correct, but Marty let him know that he had become a thief and a lonely crazy man, who wasn't afraid to kill to get what he wanted.
Just as one of the androids was about to kill two bystanders, Gabriela Sanchez and her niece Maria, Marcus smashed the flux capacitor on top of the android, saving them, and preventing the future from happening. The elder Marcus, the androids, and the steel plated Yugo time machine faded from existence, and Marcus told Gabriela that the androids were merely holograms.