Hiro glanced in stores and down streets. He searched everywhere before finally looking up. A puffy white figure strolled along the edge of the elevated train tracks. Hiro gasped as a train rushed past and almost knocked the robot off of the ledge. "Baymax!" he shouted, but he had lost him again.

Hiro chased the cable car as it headed downhill. "Hey! Hold up! Stop!" he yelled. But by the time Hiro reached it, Baymax had hopped off.

He continued to follow the sounds of traffic chaos, knowing it was probably Baymax who was causing the commotion.

Baymax held up the glass petri dish. "I have found out where your tiny robot wants to go."

Then he saw Baymax! He was standing outside a grimy old warehouse.

Hiro was almost out of breath. He stopped and took a look around. He'd been too focused on Baymax to notice, but now he realized he was in a run-down, industrial part of town. Everything looked dark and abandoned.

"Baymax!" Hiro shouted. "Are you crazy? What are you doing?"

Hiro looked at the petri dish. The microbot was really banging against the dish in the direction of the warehouse. Hiro had thought the microbot was malfunctioning, but now he had to consider the possibility that maybe it wasn't.

Moments later, Hiro was standing on Baymax's giant head. "Please exercise caution," Baymax warned as Hiro partially deflated the robot's head with the weight of his feet. "A fall from this height could lead to bodily harm."

"There's a window," Baymax said, pointing to an upper story.

Even so, how could he get into the warehouse? He ran to a metal door and pulled on it, but just as he had expected, it was locked.

"Oh, no."

Hiro climbed through the window and into the warehouse. In the dim light, all he could see were oil drums on a lower level.

Baymax suddenly made a rude noise. "Excuse me," the robot said, "while I let out some air."

At Baymax's declaration, Hiro looked back. He saw that the robot had gotten stuck trying to get through the window.

"Yes," Baymax replied, and Hiro pulled him through. "It will take me a moment to reinflate."

"Uh, okay." Hiro understood that to fit through the window, Baymax had to deflate a bit, but the sound was really obnoxious -- and loud. "Are you done?" Hiro whispered.

Leaving Baymax behind to inflate, Hiro nervously went down a flight of creaky stairs. As he passed a row of oil drums, he thought he heard a low drone. "Hello?" he asked, but no one answered. He grabbed a broom.

Hiro turned a corner and saw a sealed-off area in the middle of the warehouse, covered with tarps. He crept closer and peeked inside. He was shocked to see a large machine manufacturing… Could it be?… Yes! Microbots! Lots of them. They were being spit out by the machine onto a conveyer belt.

"Fine," Hiro said, rolling his eyes. "Just keep it down."

"Hiro," a voice suddenly said.

"My microbots?" Hiro whispered. "Someone's making more."

"GAH!" Hiro gasped and turned around. It was only Baymax. "You gave me a heart attack!"

Baymax nodded and waddled closer. "My hands are equipped with defibrillators. Clear," he said as he rubbed his hands together and held them up to Hiro's chest, ready to shock his heart into a normal rhythm.

"Stop! It's just an expression!" Hiro said, and he walked over to one of the oil drums. He opened the lid and looked inside. It was filled with microbots. He looked up and down the aisle and realized that all the drums in the huge warehouse were filled with microbots!

Suddenly, the microbot in Hiro's petri dish started to shake, this time banging the petri dish on all sides.

Hiro gave Baymax a look of terror and yelled, "Run!"

"Oh, no," Baymax said again as a low, angry buzz rose from the oil drums all around them. The thousands of microbots rose out of the drums in a menacing swarm and headed toward Hiro and Baymax.