Invader zim: Hi-Skool (chapter 1)

Zim sat on the purple sofa that sat in the living room. His head was against the back of the sofa, and his eyes were closed. He then began to hum a strange tune.
GIR, who sat beside of him, was laughing and carrying on about The Angry Monkey show, and the other usual things he carry's on about.
Suddenly the room was silent, other than the purr of the TV. GIR stopped his bickering, and turned to Zim. There was a deep frown on his face, which was unusual for the tiny robot.
Finally GIR spoke, "Mastah? Why are yew so sad?" He asked.
Zim opened his eyes, and sat up, "It's nothing GIR. Just continue watching that disgusting show, and leave me ZIM, at peace." He then closed his eyes and rested once more.
GIR knew that he was not telling the truth, but he also knew he did not want to bother his master while he seemed sad, so Gir returned to his watching of the TV.
Suddenly the doorbell rang, and the security alarm went of, "WARNING, INTRUDER ALERT! UNATHERIZED PERSONEL IN YARD!" It rang.
Zim stood and hurriedly put his human disguise on. His disguise was now different, now he wore normal human attire, and his wig was longer, but it was still black, and his contacts were still blue. He put on a pair of black jeans and a black and red stripped hoodie. Then his wig and contacts, and hurried to the door.
He opened it expecting the filth of that hippo headed boy Dib, but instead he was surprised to find not did, but Dib-sister.
"What do you want, human filth!" Zim yelled.
Gaz stared at him for a moment before responding, "You left this at our house." She handed Zim, one of GIR's dog costumes.
Zim's eyes widened, he did not remember leaving it there on his last attempt to destroy Dib. He snatched it quickly out of Gaz's hand, and threw it inside.
"Why did you bring it?" Zim asked.
Gaz's face turned a little red, which made Zim wonder if her head was going to explode. She then pulled out her Game slave 4, and began to walk away. Zim did not mind, he was glad that she did not explode all over his base. He looked at the ground to see that Dib-sister dropped something.
He bent over and picked it up, and it was a note. It had Zim's name on the outside, and it told him to read it when he was alone. He chuckled, "Foolish human why would the almightily ZIM, waste his time with a petty note?"
He walked inside, and threw it away. Then he removed his disguise, and went to his elevator in the living room. Zim now had to be very careful with the elevator, because now that he was taller, for reasons unknown, it was dangerous to be in the elevator. It just simply was not ready for his new weight.
He went down, into the computer operation room, and sat in the master chair.
He laid his head back and closed his eyes, "Computer, I want you to do a scan. Tomorrow skool starts again, and I need to know, what is wrong with me?"
"Scan in progress." The computer rang, and then it said, "Scan complete, finalizing data."
Zim began to hum again, at least he might find out why he has been so slow recently, and then again, he had a good idea why. Then the memory flashed into his mind, and pain welled up inside of him. He hummed louder to force the pain away, and it did seem to dissipate.
He smiled, when the computer said, "The results are finished, do you wish to know?"
"Yes, I do." Zim said, but little did he know, that he really did not need to know these results, because he already knew them himself.