The moment we got to the Institute, I hopped off the moped, ran into the Institute, located my suit, and struggled into it. I felt really bad leaving the rest of my friends to fight Callaghan, but I had to hear what Abigail had to say. I wonder who help put Baymax's suit on.

"We better hurry," Clara said, as soon as I came out with my armour all set, and she briefly turned visible again. "Where's Baymax?"

Just as she said those words, Baymax flew over and landed right beside me.

"That enhanced scanner must be working well, isn't it?" I asked Baymax. "Now you can track wherever we are."

Baymax blinked. I guess he agrees. "Get on, Hiro. There's something you should see."

I climbed onto Baymax's back and we flew away, while Tadashi and Clara activated their jet packs and took off to find the first of Callaghan's bots that wasn't defeated. As we soared through the sky, I saw that some people stayed outside kicking some bot ass, while other people were running for what was left of cover. Out of the corner of my eye I saw some of Abigail's bots fighting the zombie-like ones, slicing them up and breaking their operative mechanisms.

I nodded to myself. So far, it was going well.

Honey Lemon and Fred teamed up, creating lots of smoke first to confuse the zombie bots and cause them to lose their senses before Fred came in with the fiery kill that burned their control units. I saw Gogo and Wasabi moving through the huge throng of microbots faster than they did before, the first time we successfully defeated Callaghan, slicing them up into small pieces so that they were unable to move around anymore. Gogo had Clara's remote control (I think Clara gave it to her before she and Tadashi started attacking the bots) and the microbots were sucked up in an empty vacuum. As for Tadashi and Clara—well I couldn't see Clara, but Tadashi's new powers enabled him to trap the bigger bots into the dirt, while someone bashed their brains in the air and knocked them out. I suppose that was Clara. Her invisibility was working fairly well.

"HIRO HAMADA! WHERE ARE YOU?!" Callaghan boomed. "SHOW YOURSELF OR FACE YOUR DOOM!"

Oh no. Did he really have to ask for me right now?

Baymax looked at me uncertainly. "Your heart rate is accelerating. You must be scared."

"I am!" I cried. "I don't know how I seem to haunt him so much, though. It's worse than Tadashi's case. What should I do?"

Baymax landed on a nearby roof. We sat down to think.

"Is sacrificing yourself what your friends want?" Baymax asked me.

I gave it some thought. That never crossed my mind before. "I—well, I don't know…sometimes I question my loyalty to my friends, but it seems like I value my own life just as much as I value theirs." Then I told Baymax everything that Abigail told me.

Baymax listened intently before thinking. "See what Professor Callaghan wants. Fight if you need to. The whole city is relying on you." He paused before continuing. "Abigail is right. Callaghan is no longer a normal and healthy person. It would be difficult to reason with a distressed and angry person. But try your best. I know you can do it."

I took a shaky breath. The rest of my friends seemed to be doing really well, but I had to finish the job. This was my fight, and what I do eventually has more impact. "Baymax, you've once sacrificed yourself for my safety in the portal rescuing Abigail. Now it's my turn—for everyone in San Fransokyo." I wasn't prepared. Would everyone care for me, that I was just about as gone as Tadashi was before I found him again? Tears welled in my eyes, and I quickly wiped them away.

"You would do well," Baymax said. "It's your turn to make peace with Callaghan and restore happiness in San Fransokyo. No one will forget you. What you would do would be a true hero's act." He paused before saying the last words that I remember him saying in the portal before we had to part. "I will always be with you."

I knew exactly what that meant. This was goodbye, not just to Baymax, but to everyone I ever knew. The only way for San Fransokyo to restore its former glory is for me to give the sacrifice, the final thing that gets everyone thinking about the true hero of the battle. If I was to die today, I would have to make my sacrifice worthwhile.

"Thank you, Baymax. Me too," I told him, giving him one last hug before climbing up his back again and making the flight to where Callaghan was standing. He stood on top of one of the supports of the Golden Gate Bridge, wreaking havoc on all the vehicles and even breaking all of the suspension cords, causing a lot of the debris to fall in the water with a huge splash.

"This is pretty serious!" I cried. "He's got to stop."

Baymax soared upward so that we were level with Callaghan, who stopped what he was doing just to face me. Once upon a time he had a white Kabuki mask on, and now the mask was pure gold, with the same designs on them. Other than that, he looked no different from the villain I once knew. And just looking at him, it reminded me of something that Clara told me back in the café—a bit like some weird guy called Hitler controlling the Nazis back in the olden days of the second world war. Oh geez. Don't get me there, I'm not ready for history yet. But that would be another story

"It's over, Callaghan," I called for his attention.

Callaghan turned to me, though he kept his attention on making the cars crash against each other with the microbots.

"So he has finally come," he said. "Hiro Hamada, robotics genius, hoping to be better than his brother."

"I don't want fame," I corrected him. "I just wanted my brother back. Now he's here."

"And so are you," he told me. "But soon you won't be. Say goodbye to everyone you once knew, everything you once had. The fate of this ciety lies in my hands, and you won't be alive to see it."

Callaghan raised his hand, and an army of huge dinosaur robots advanced towards us. The closests one, probably the head of the group, opened its mouth, preparing to spit out a tongue of fire straight at me and Baymax.