"Will apprehending the man in the mask improve your emotional state?" Baymax asked. Hiro nodded. "Absolutely." Then he cracked his knuckles and turned his computer on. "All right. Let's work on your moves."

Hiro couldn't wait to get started. He had Baymax stand in the center of the garage. "Okay, arms up," he said as he pulled an electronic device from a shelf. He quickly scanned Baymax, then rolled his chair over to his computer.

He downloaded the scanned image of Baymax to his computer. A 3-D model of Baymax's soft body appeared on the screen. With Baymax peering curiously over his shoulder, Hiro began to program a new fighting chip.

"Now let's take care of this," he said, poking at Baymax's vinyl belly. Hiro turned to a different computer screen and uploaded images of armor from throughout the ages. Hiro enjoyed mixing and matching the pieces until he came up with a suit of armor he liked.

On another screen, Hiro downloaded a martial arts video. With a smile, he linked the karate moves to the model of Baymax. Once the program was running, Hiro turned his chair around and looked at the robot.

Hiro finally added the last piece of armor to Baymax's soft body. "Now, that's more like it!" he said, admiring the hard shiny discs.

As he fitted each armor segment to Baymax, the fighting chip programming continued on another screen. The 3-D Baymax model was learning elaborate karate moves with every passing second.

He typed in the code that programmed his 3-D printer. With just a push of the print button, it created three-dimensional carbon-fiber objects in minutes. Hiro grabbed the first piece of armor and rolled his chair to where Baymax was waiting.

Hiro triumphantly placed a helmet on Baymax's head.

But Baymax simply stared at his armor. "I have some concerns," he said, tapping his hard belly. "This armor may undermine my nonthreatening, huggable design."

"I cannot be sick. I am a robot," Baymax said.

Just then, an alert came from Hiro's computer: "Data transfer complete." The fighting program was ready! The red chip popped out of the drive and Hiro drew a skull on it.

Hiro couldn't help laughing. "That's kind of the idea, buddy. You look sick!"

"You want to keep me healthy, don't you?" Hiro asked as he gathered a pile of wooden boards to test out the new programming. But Baymax still didn't understand. Finally, Hiro held a board in front of Baymax and said, "Punch this."

"Ha! Yes!" Hiro yelled. He held up a series of boards and gave Baymax new commands.

He rolled over to Baymax and opened his access port. Then he gasped when he saw Baymax's green health-care chip -- Tadashi's name was written on it. Hiro froze for a second. It hurt to see Tadashi's handwriting. But then he remembered why he was doing this, and slid the fighting chip in next to Tadashi's.

"I fail to see how karate makes me a better health-care companion," Baymax stated.

With almost no effort, Baymax snapped the board in two.

"Hammer fist!" Hiro said, and Baymax shattered the board.

"Back kick!" Hiro shouted, and with the grace of a ninja, the giant robot split the board with his foot, launching the pieces out the garage door.

"Knife hand!" Hiro ordered, and the edge of Baymax's hand hit the board like a guillotine.

Baymax stared at Hiro's hand and blinked. "Fist bump is not in my fighting database."

Baymax blinked and made a mock exploding sound, too: "Bata-lata-la."

Hiro continued to have Baymax practice karate moves. Baymax's work was flawless. Hiro smiled approvingly and held up his hand. "Yeah! Fist bump!"

"There! Now you're getting it!" Hiro said. Baymax nodded. "I will add fist bump to my care-giving matrix."

Hiro laughed. "No, this isn't a fighting thing. It's what people do when they're excited… you know, pumped up." Hiro bumped his fist against Baymax's and made an exploding sound.

Hiro kicked the garage door open and stepped out with a fully armored Baymax. "All right," he said. "Now let's go get that guy!"