Baymax stood in his charger while Hiro was out with his friends finishing a project together and he needed to recharge so he just stayed home. He blinked. As a robot, it was impossible to feel sorrow. So what was this emptiness he felt in his small mechanical heart? It has been there since Hiro told him that he was gone. His creator was gone. And he wasn't coming back. Baymax looked down at his feet. Or preferably, belly. He couldn't quite well see his feet because his adorable marshmallow-like belly stood in the way. But he wouldn't have it any other way, he was created like that.

He felt… sad. Was it even possible? Was this the way Hiro felt about his brother?

Was this the way he supposed to feel about losing his father? Well, Tadashi created him. It seemed only right.

Oh, Tadashi. If only he was here.

Baymax looked to his right and saw Tadashi's bed in there. His baseball cap placed over it. Untouched. Baymax blinked. He stepped out of his luggage and made his way towards the bed. He stood in front of the bed, looking at the baseball cap. He extended his chubby arms towards it and slowly picked it up. He inspected it. As far as his memory could reach, Tadashi always wore this hat.

He put it down, still looking at it.

He searched in his database for his videos of Tadashi and replayed them in his mind. It was all recorded from his point of view, so he didn't exactly saw himself.

"Tadashi? I sense that your face temperature has risen up, you are in a trance and you don't seem to have a fever. Are you feeling alright? Is this a disease I am not aware of?"

Tadashi snapped out of his trance and looked back at Baymax. He smiled at him. "No, Baymax. It's not a disease."

Baymax blinked and walked towards the computer. He placed his hand over the monitor and downloaded some information about Tadashi's strange symptoms. "Download completed. I searched over for your symptoms and I found that it's something that the person feels for someone else. Does Miss Honey Lemon make you feel like this?" Honey Lemon had walked out of the workshop a few minutes ago before Baymax asked Tadashi if he was alright.

Tadashi chuckled. "Yes, she does."

"Then I must make an antidote for this sickness."

Tadashi chuckled again. "No, Baymax. It's not THAT kind of sickness."

"Then what kind of sickness it is then?"

"It's called love, Baymax." Tadashi sighed as he looked at the ceiling in a love-struck trance. "Is a sickness that can't be cured and it happens to every human."

Baymax looked at him. "Is it emotional?"

"Yes, it is."

"I see. I'll record that information in my memory card." Baymax said. "I still don't quite understand it."

Baymax blinked as the video stopped playing. That was right, Tadashi felt this strange thing called 'love' for Miss Lemon. Later, Tadashi had explained that love could be felt towards a mother, a father or a brother. Even friends. So, Baymax felt this affection towards his now dead creator? Was he capable of love?

He looked at the baseball cap again. If he could cry, he would have. Crying is a natural reaction to pain. Physical or emotional.

He missed Tadashi.

"Tadashi." He said.

The emptiness was still there. It did not matter how many memories of Tadashi he had, he felt empty. And that came from a robot that was filled with air.

"Tadashi." He repeated, like if he was calling for him. He wanted his creator to come back home and upgrade him and spend time with him. But that was not going to happen. He knew because Hiro told him.

"Tadashi." He said, looking at the bed with the baseball cap that sat still at the edge. "Tadashi." He repeated.

Where was Tadashi?

"He's gone, Baymax." Hiro said as he got up and grabbed the sliding door's handle.

"When will he return?"

Hiro closed the door. "He's dead, Baymax."

Baymax was confused. "Tadashi was in excellent health. With the proper diet and exercise, he should have lived a long life."

"Yeah, should have…" Hiro said, his voice filled with sadness. "There was a fire and… and now he's gone."

"Tadashi is here."

"People keep saying Tadashi is not really gone as long as we remember him." Hiro sat on his chair. "It still hurts…"

"I see no evidence of physical injuries."

"It's another kind of pain. It's emotional, like when you lose somebody."

So love was like pain. They were equal, yet, different. And he felt those right now. "Tadashi." He repeated one last time.

And Tadashi did not came back.

Tadashi is here, he had told Hiro. But he was not. He wanted him to be here, right here and right now. Not in just some… video.

He did not understood death. He knew it was cold and the body stopped breathing, but after that, there was nothing. Some people told Hiro that Tadashi was with them. But Baymax couldn't see him. Where was Tadashi?

"Baymax?" He heard Hiro say. Baymax turned around and saw Hiro with his usual jacket on and a sad face. Hiro looked at Baymax and then at the baseball cap. "I heard you calling for Tadashi." He looked down. "I… I already told you he is not coming back."

Baymax looked at his belly. He finally saw it. He understood. "Tadashi is not here."

Hiro looked at Baymax with surprise. "No, Baymax. He is here."

Baymax looked up. "But where is he? Where did he go? My sensors don't pick up his heart rate or body heat."

Hiro approached him and placed a hand over his vinyl chest. "Tadashi is here."

Baymax looked at Hiro's hand. "That is not quite possible. A human cannot live inside me."

Hiro chuckled. "Maybe one day you'll get what I mean."

The robot looked at the young teen. He blinked. "I miss Tadashi."

The young teen looked at the robot in surprise. He gave Baymax a weak smile. "I miss him too." He grabbed the baseball cap from the bed. Hiro sighed as he looked at it. He rubbed the edge of it with his thumb in affection. He smiled and looked at Baymax. He adjusted the back of the cap to make it bigger. He raised his arms and placed the baseball cap over Baymax's head. A perfect fit.

"I'm pretty sure Tadashi would have wanted you to have it."

Baymax looked at Hiro and then at a mirror on the back. He walked towards it and inspected the cap on his head. "Tadashi is here." He said.

Hiro smiled. "Yeah, he's here. As long as we remember him."

Baymax looked at his chest in the mirror and played a video of Tadashi teaching him medical things and other things that he couldn't quite understand like 'love'. And now he understood it. Baymax would have smiled if he could. "Tadashi is here."

I hope you enjoyed this little one shot. I just had to add in the end Baymax wearing Tadashi's baseball cap. The idea was too cute to pass on. Review.