A month later, Hiro was the only one who hadn't given up hope.

"There's got to be somewhere we haven't checked!" He exclaimed, pacing back and forth. "What about Callaghan's house?"

"We've checked there three times, Hiro." Wasabi sighed. "There's nobody in there."

"Well, let's check again!"

"Hiro…"

"If he's not there, we can give up this whole thing."

"Alright…" GoGo said with a sigh.

"Come on, let's go!"

They all climbed on Baymax and he flew them downtown towards Callaghan's house. The second they landed, Hiro threw open the door and ran inside. Just like the last three times, it seemed completely empty.

"We have to look around." He thought out loud. The others exchanged glances, preparing to comfort Hiro when Tadashi was nowhere to be found. He didn't pay any attention to them, and thoroughly searched every room. He looked under furniture, in closets, and in every other place that there could conceivably be anything, but nothing seemed out of the ordinary. Letting out a sigh, he slumped down on the floor, leaning against a bookshelf.

"Hiro, we're so sorry…" Honey said quietly.

"He…he's really gone…"

"Look, buddy…" Fred started, but then stopped mid-sentence. "Wait a second…" The bookshelf had moved slightly, and behind it was what appeared to be a hole in the wall. "Maybe we shouldn't give up just yet."

"What?" Hiro looked up at him and stood up. Without answering, he started pushing the bookshelf sideways along the wall. Baymax joined in, speeding up the process, and everyone gasped at the sight of a doorway that had been hidden behind it.

"I knew it!" Hiro exclaimed. "Come on!"

"Calm down, little man." Wasabi said quickly. "Don't risk running into danger. Let's take it slow." Together, they all tip-toed through the passageway, down a flight of concrete stairs.


"Master Callaghan." Tadashi said, walking over to the former professor. "I'm picking up a signal from the security system. There's an intruder coming down the east staircase."

"What?" His eyes widened, and he quickly dashed over to a large screen displaying the live feed from the security cameras he had installed. "Big Hero 6." He snarled. "Looks like your training needs to be cut short, Tadashi. You need to fight now."

"I'll make them wish they never set foot in our headquarters." He snarled, walking out the door with his fists clenched.

"Wait." Johnathan halted him. "We need to catch them by surprise. Callaghan, come with me. Tadashi, you're our greatest weapon. You'll join us last."


"My sensors are detecting three people. The signals are all male." Baymax said.

"One of them's got to be Tadashi." Hiro whispered.

"They are coming closer."

"Shh!" Wasabi shushed Baymax. "We can't let them know we're coming."

"Oh, we already know." Callaghan said stepping into view. "And don't bother whispering. We can see and hear everything in here."

"Callaghan." Hiro snarled.

"It's nice to know we don't have to concern ourselves with introductions." Johnathan smirked, stepping out beside his partner. Hiro raised an eyebrow.

"I know you two have Tadashi. What have you done to him?"

"They only told me the truth." The other two scientists stepped aside, revealing Tadashi, who was strolling towards them casually, but with an air of malice about him. Hiro let out a gasp. Tadashi had looked different in the hospital, but now he was nearly unrecognizable. All his limbs but his right arm were metallic, and made electronic whirring noises with his every move. His right eye had been replaced with a cybernetic one that practically glowed bright blue, and there was a small black barcode tattooed below it. His expression was darker than any of them had seen before. This wasn't the Tadashi they knew and loved.

"Guys, he's a cyborg!" Fred exclaimed. "That's awesome!" Hiro didn't see it in such a positive light.

"Tadashi…what have they done to you?" He asked again.

"They made me see how things really are. You are the enemy, not them."

"What?"

"Tadashi, attack them."

"Yes, Master Callaghan."

"Master?" Hiro managed to cry out before Tadashi charged at the group. His arm extended out, grabbing a still awestruck Fred and throwing him against the wall brutally

"Freddie!" Honey shouted, then quickly pressed the buttons on her bag, mixing chemicals together. A pink sphere emerged, and she threw it at him. It expanded in a bright pink foam, encasing his legs, but he quickly jumped out of it; thrusters on the bottom of his feet pushing him upwards with great force and levitating him in the air a few feet above the ground. He zoomed over to her, grabbed her bag, and crushed it in one hand, then turned on her with a smirk. Wasabi quickly sprang into action, slicing at him with his lasers, but he deflected them with ease and tossed him and Honey into the jail cell that he had woken up in ages ago.

"That's it." GoGo scoffed, throwing one of her disks at him. He quickly jumped up, flipping upside down and hanging down from the ceiling.

"Nice try." He chuckled and jumped to the ground, grabbing the disk out of midair and breaking it in half. He tried to pursue GoGo, and she sped away from him, circling the room with speed that was usually unmatched. But Callaghan had taken everything into account, and Tadashi managed to catch up with her with ease. Grabbing the speedster by the back of her suit, he picked her up off the ground and threw her in the cell with the others, and added Fred to the bunch for good measure. He locked it, and turned on the two who remained.

"Baymax, stop him!" Hiro shouted. The robot reached for his creator, but Tadashi ducked, and ripped the armor off of his chest. A small knife emerged from the cyborg's finger, and he ripped open Baymax's vinyl exterior.

"Oh no." He said, deflating quickly. Hiro glared up at his brother. Now, it was personal.

"Tadashi, stop this!" He commanded.

"I don't take orders from you." He answered, grabbing Hiro by the throat and pinning him against the wall. The teenager struggled to get away, but his grip only tightened.

"Good job, Tadashi." Callaghan commended him. "Now, kill him." Hiro tensed, preparing for the worst, but to his surprise, his brother's grip loosened significantly.

"You never said I'd be killing anyone, Master Callaghan."

"But Hiro is the enemy."

"You said we'd stop him, not murder him." He dropped Hiro and turned to face Callaghan.

"Stop defying me, Tadashi."

"I'm sorry, Master Callaghan. But, I don't feel comfortable killing anyone."

How you feel doesn't matter. Just kill him!" Johnathan snarled.

"If I kill him, that'll make all of us as bad as he is." He glanced over at the members of the team, who were watching in confusion and fear. In a flash, he sped over to the cell, unlocked it, and pulled them out. They rushed to Hiro's side and helped him to his feet. "Get out of here. All of you. And never come back." He snarled.

"What are you doing?" Callaghan asked angrily.

"I can't follow orders this time, Master Callaghan. But, I can get the enemy to leave." The team all ran out, dragging a deflating Baymax with them. Callaghan and Johnathan watched helplessly, knowing that Tadashi had made up his mind, and they couldn't do anything to change it. As soon as they were out, they approached him angrily.

"You traitor!" Johnathan snarled. "Do you realize what you've done?"

"I…I…"

"You disobeyed us, and now our greatest enemies know where we are and what we're doing." Callaghan shouted, giving him a vicious slap.

"I'm sorry, Master Callaghan."

"Sorry won't cut it. Now, follow me to the lab. You need to be punished." Tadashi looked down at the floor in shame.

"Yes, Master."