OU’VE NEVER SEEN just how mega a megalopolis can be until you’ve seen Mexico City. I guess there might be bigger burgs in like China or something, but boy howdy, Mexico City seems endless.

Anyway, the Bane of My Existence and I had agreed to one more air show, and of course it was the one in Mexico City, where Dr. Wonderful would be meeting us.

So we were over a ginormous open-air stadium, the Estadio Azteca, which held about 114,000 people. Every seat was filled. We’d changed the choreography and order of stunts since the last show, so if anyone had made a plan to take us out, they’d have to rethink it. Around us, mile upon mile of densely packed buildings stretched as far as we could see, and we can see pretty dang far.

“I need a scuba tank,” Nudge said, flying over to me. She was holding her nose with one hand. “And a face mask.” She gave a couple of coughs and shook her head, her eyes watering.

“I assume you’re referring to the wee pollution problem?” I said, raising my voice to be heard over the wind and the multitudes cheering below. The people in the stadium were looking up to see us silhouetted against a thick gray sky. But it was not a cloudy day. The thing is, with nineteen million-plus people and four million-plus cars and a bunch of businesses making stuff, Mexico City is incredibly, horribly, nauseatingly polluted.

Which was why the CSM wanted us to be there—to bring international attention to it. When Dr. Wonderful was prepping us for the air show, she’d told us that there had been half a million pollution-related hospital cases just in the past year.

Now we were wondering if we were going to raise that number to half a million and seven.

“I’m getting a headache,” Gazzy said, circling closer to me. We split apart in a six-pointed star, with Total in the middle, and the crowd below went crazy. Like a huge, rolling wave of sound, the chants came to us.

“We have the power! The future is now! Kids rule!”

I raised an eyebrow at Fang. “Kids rule?”

He shrugged. “I can’t control what they quote from the blog,” he said. “What am I gonna say? ‘More power to grown-ups?’ I don’t think so.”

“How many readers do you have now?” Fang had started a blog months ago, using our super-duper-contraband computer. He had his own fan clubs and everything. Girls sent him ridiculous

e-mails about how wonderful he was, what a hero, etc. It was enough to turn your stomach.

“About six hundred thousand log in pretty much every day,” Fang said, automatically scanning the airspace around us. He and I suddenly soared upward, facing each other, about two feet apart. The crowd below gasped, and I knew it looked impressive as all get-out.

Then Iggy zoomed up to join us, and he, Fang, and I made a triangle, our wings moving in perfect order so that we didn’t whap each other on the upstroke. Total hovered way above us, like a star on top of a Christmas tree.

A hundred yards below us, Nudge, Gazzy, and Angel were a triple stack of bird kids, centered one over the other, moving their wings in unison: everyone up, everyone down. At Gazzy’s signal, they all turned and started rocketing earthward, still precisely stacked.

Fang, Iggy, Total, and I counted to ten, then angled downward also: it was time for us to land on the field. Supposedly they were going to give us some kind of award.

“You’re national heroes,” Dr. Amazing had said earlier, pushing her, yes,red hair out of her eyes while Fang watched her with interest. “Not only here, but in other countries too. You guys are so young, but you’ve accomplished so much and exposed so much evil. Plus, you helped publicize the melting of the planet’s ice, and spoke to Congress. You’re amazing.”

Who was she beaming at? Yes. Fang.

Who, exactly, had gotten up the nerve to speak to Congress? That would bemoi.

But, judging from Brigid Dwyer’s unprofessional adoration, Fang alone had just saved the entire known world with one wing tied behind his back.

It had been all I could do not to trip Brigid on her way out. Which was stupid, because why did I care? Never mind. Forget I asked.

The field below—big enough for the World Cup, the Olympics, and anything else where 114,000 people suddenly needed to be at the same place at the same time—beckoned us. There was a line of uniformed security guards hired by the CSM ringing the perimeter to protect us.

I saw Nudge, Gazzy, and Angel land flawlessly and wave at the crowd as a hundred thousand cameras flashed. Unfortunately, since a camera flash bears a striking resemblance to the flash a gun makes when it’s fired, by the time I reached the ground, I was so twitchy and pumped full of adrenaline that I felt like I might hurl.

We joined the rest of the flock on the green turf and then all automatically circled, facing outward, as if we were six (and a half) cute little covered wagons warding off Indians who were inexplicably ticked off that we’d taken all their land and given them colds and killed most of them.

The crowd was roaring too loudly for us to hear guns. Heck, we wouldn’t have been able to hear a chopper. It was, pretty much, the most nightmarish situation I could possibly imagine, without literally involving a dog crate.

And you know what’s coming, right?

Yeah. The actual nightmare part.