A.N. This chapter includes some mildly sexual content, viewer discretion is advised.

Chapter 4

Over the next several days, Zim went to the hospitals in major cities all around the world. Technically, it was over the next several nights. He used the cover of darkness to hide his Voot cruiser as he approached his destinations, landing on the helicopter pads on top of the large buildings and sneaking inside.

It was made difficult by the fact that there was always staff inside no matter what time it was. Even in the middle of the night, the hallways were lit and there were plenty of people to see him. He had to be very sneaky, and act like he belonged there. Several times, though, he just had to run through the rooms, planting the disease where it could be spread to patients, and quickly getting out.

When he almost got shot by a security guard, he decided to take a break and see what effect he was achieving.

It was already working. There have been hundreds of deaths, and people were miserable, even if not related to any of the victims. Thousands more patients were suffering from rapidly deteriorating health, and hospitals were desperately trying to find out why. They suspected the unknown person who has been raiding the hospitals, of course. But they couldn't track him. While they knew the medicine was being tainted somehow, they had yet to identify the chemical causing the problem.

Zim decided to visit Gaz at her house one night to tell her all about it. He was happy enough, just because one of his plans was finally successful. But he was sorry about the unnecessary loss of life.

"It had to happen. I don't like it either, but I'd rather it be now then later, when the irkens purge the hospitals of anyone who's too sick to work for them," she said.

"Yes, they will do that," Zim replied, nodding. "Still... it's hard, having to do this."

"Hey, you'll soon be done with it, and then we can leave. Leave, and forget all about it." Gaz kissed him to make him feel better. He leaned closer, wrapping his arms around her and responding.

Dib still didn't like that they were together, and heavily suspected that Zim was behind all this. But he couldn't prove it, and spent most of his time at his dad's lab working to find a solution with the rest of the great minds of the world.

So Zim and Gaz were alone, and they planned to enjoy it.

"Ah, being with you has made me feel so much better about all this. Yes, your icky sympathy has rubbed off on me, but that's fine. I'm still happy. My plan is succeeding, and my Tallest are impressed with the results. They're heading this way, but won't be here until a month from now."

"We've got a lot of time to ourselves, then."

"Yeah... A lot of time for the humans to fall into complete depression with this happening. More time for me to infect smaller hospitals." Zim held her close. "I can't wait to leave. Just get out of here, go back to Irk. Where I'll be appreciated for what I've done, and can get a house, and..." He laughed. "It'll be strange, being a civilian. But I don't want to be in the military anymore after all this is over. Once an Invader conquers a planet, they are expected to move on to another. But they can be honorably discharged and become a civilian. Get a normal job, live in a town or city somewhere... raise a family..."

Gaz rested her head against his. "Do you want a family?"

"Maybe one day. For now, you're all the family I need." He nuzzled her. "While we're sharing this moment, I was wondering... do you want to be mine? Or... hmm, how do humans say it..." He frowned, trying to find the words in English. "I like being with you. You're fun and caring, always here for me... I want you to stay with me. For the rest of our lives. How about it?"

Gaz thought about it. She loved Zim. But would she love him forever? ...Yes, she would. He was unforgettable, and she doubted she could stop loving him. "Yes, I want to be with you."

He smiled. "Then it's settled. We should be mates. It would mean a lot to me."

"Mates?"

"A mated pair. A couple. You know..." Zim gestured vaguely.

"You want to have sex?"

He quickly looked away, blushing. "Well, I wasn't going to put it that way. But..."

"Because I've never done that before, but we can try."

"Really?" He looked back at her, antennae perking. "Oh, I've never done it either, but we can certainly try! You want to?"

Gaz raised an eyebrow. "Right now?"

"Yeah, if you want. Or we can wait."

"Dib will probably be gone for hours working with Dad. I say we do it now, while we're alone."

Zim nodded, standing up and stepping back from her so he could take his boots off. "Good idea. You know, I've never really wanted to do this before, but now that I'm with you, I do want to. Funny how that works, huh?"

"Yeah, I feel the same way. I've thought about it before, but didn't care either way about doing it. But the idea of doing it with you..." She smirked. "I like that. Hey, you better be careful, okay?"

"I will be. We're both beginners, we'll have to be careful."

Gaz waited until Zim had taken his boots and gloves off, then pulled him over to the bed, sitting down and kissing him on the lips. He smiled and tilted his head so it was more comfortable, standing in front of her with his hands on her thighs. He pressed his thumbs against them, kneading slightly through the fabric of her jeans.

Slowly, she allowed him to climb over her and push her back down against the bed, but she made it clear that she was still in control. She tugged his shirt off and dropped it onto the floor, and drifted her hands down his shoulders and arms. His skin was so smooth, almost soft under her fingers, yet bore very few scars. She knew he could heal from almost any injury very quickly, but didn't know that also prevented scarring.

Unless irken scars just don't really show up as plainly as ones on human skin do.

She casually rubbed her finger against one on his upper arm that she could see, wordlessly asking him what had hurt him bad enough that it was still visible.

Zim glanced over at the arm. "Oh, that. You see, back in the Academy, we learned many different forms of combat. Including how to use knives and swords. And we practiced with real weapons. If you died during training... oh well, you weren't useful anyway. But I was practicing with the teacher because everyone else had gotten partners and there was an odd number of us in the class... He was not a nice man." Zim shook his head. "He hit me in the arm with the blade, cut down until the bone stopped it. It... hurt."

"That's an understatement," Gaz commented.

"Heh. Looking back on it, I don't really remember the pain itself, but I remember a lot of blood and yelling. A few students were hoping I'd die." Zim stared off into space for a few moments. "The medical bay gave me candy after bandaging my arm. Anyway, it healed, and now I'm left with this ugly scar."

"It's not ugly at all." Gaz traced the outline of it. "Bodies aren't all one color. It's nice to see some imperfections." She reached down to his hand, squeezing it.

He smiled and kissed her, and with his other hand, grasped her sweatshirt and began pulling it off. It had been cold today, so she was wearing another shirt underneath it. He also pulled that off, and set both down lightly on the edge of the bed.

"Oh, it can go on the floor, I don't care," she said, batting them out of the way. "They're going to fall anyway."

"All right." Zim examined what he could see of her now. He's seen her in nightgowns that showed off her shoulders, sure. But now he could see her entire upper body. Well, besides her breasts, which were still covered by yet another garment. He could worry about that later, he knew how shy human ladies could be about it.

He traced his claws lightly against her collarbone, pressing against it slightly, and then down, across her sternum. He raised them and moved out to the ribs. She was thin enough that he could easily feel the bones through her skin, and while it felt odd, it was also very intimate being able to feel her like this, and he liked it.

She let him get his fill of looking at her, and lifted her hands to his body, stroking it gently and urging him down closer. When she dug her fingernails into the small of his back, he actually moaned.

Immediately, he blushed, looking away. "Did I do that?"

"Yes, you did."

"I... didn't know I could make that noise... um..."

Gaz slid her fingers underneath his PAK. "Make it again." She rubbed the sensitive skin, and his back curled in, as he groaned again in pleasure. "Now we're getting somewhere." She stopped, instead reaching up to pet his antennae, massaging along the lengths before twisting her fingertips just lightly around the tips.

"Gaz..." he purred, tilting his head to bring the antennae closer to her.

She amused herself by petting them for a while, then lowered her hands to his hips, pulling them against hers to tell him that she wanted to continue.

"Oh, right. Mating. Just let me..." He put his hand on the front of her jeans, tugging on the button a little, but nervously glancing at her for permission.

She nodded, and he undid the button. Once he figured out that they had to be unzipped too, he was soon pulling them off, having to sit back to remove them completely. He tossed them aside and looked her over again. She had such a pleasing body shape. Not too thin, but not too big. Her arms were muscular from years of taking weight lifting classes in school, as she hated the 'weak girl' stereotype. The muscle was also more noticeable in her legs and partly up her abdomen, and he ran his fingers along these spots.

"I would not want to get into a fight with you," he commented, grinning.

"No, you wouldn't. And I've been wanting to get into a good fight lately." She shivered a little, but wasn't sure if it was because of the cool air or the way he was touching her.

"All right, I'll keep that in mind. If anyone wants to fight, I'll send them to you." He continued to look her over. Her skin was pale from years of staying inside watching TV or playing games. She didn't like going outside, especially not now, with how cold it was. She went to a summer camp one year, and that was the tannest Zim had ever seen her. But that soon faded, and she didn't want to go back and be eaten alive by bugs again.

Because of how pale she was, it was easy to see the subtle lines in her skin. The scars from unknown incidents as a child, the splotches and freckles that any body had. There were stretch lines from growing a little too quickly for the skin to keep up. And all of it made her beautiful. In all her imperfections, she was perfect.

Zim leaned down to kiss a birthmark on her hip, smiling when she giggled. She didn't laugh often, so he always enjoyed it when she did. Then he straddled her, rubbing against her just a little. Even through the clothing still on them, the pressure made both of them moan softly.

He wrapped an arm around her back, lifting her up so they could kiss. When she pulled away, she went for his neck, nipping it and tugging hard on the skin with her teeth.

He groaned in enjoyment, and she could have sworn she felt the bulge in his pants grow harder. So he liked biting, huh? She could work with that. Lowering her mouth, she found where his jugular vein was and bit down there, suckling until a bruise formed. He trembled, and pushed his hips down a little more firmly, telling her how much he wanted to keep going.

She was nervous, sure. But they trusted each other. As long as they were careful, this could be very enjoyable. It was natural, she told herself. Her hand drifted down to his rear, fingers sliding under the waistline of his pants and squeezing it.

He hummed softly, though it turned into another moan when she bit him right under the chin, and he actually tilted his head back for her. She licked the new wound, having managed to break the skin on that one. There was a small amount of blood, but it soon stopped. He really did heal quickly...

"Gaz... I want to keep going," he said quietly, and she felt a thrill at the power she had over him. He was usually so confident, so arrogant and convinced that he was in control. But right now, he wasn't. He was on top of her, yet he was waiting for her to let him keep going. You didn't find that trait often in men.

"I'm sure you do," she replied, kissing the corner of his mouth. "Go ahead, I want you to."

He moved then, leaning her back down to kiss her properly, deeply. As he did, he slid a hand under her back, fingers struggling to undo the clasps on her bra.

Gaz moved the hand that was on his backside, now sliding it between their bodies and swiftly unfastening his pants, opening them. By now, she could feel how much he was straining down there, and he actually sighed in relief.

She was just starting to edge the clothing down, and Zim had finally managed to get one hook of her bra undone, when-

"WHAT THE HELL?!"

Zim shouted and jumped back, and when Gaz sat up, she accidentally pushed him onto the floor. He started to get up, but then Dib stormed into the room and kicked him, hard, in the gut.

"What were you doing to my sister?" he yelled, kicking him again while he was down.

"Dib, stop!" Gaz shouted, getting up and punching him in the face. He backed away, hand flying to his face as blood poured out of both nostrils. He stared down at the liquid, then growled, throwing a punch back at her. She hadn't expected him to hit back, and it managed to catch her on the ear as she tried to dodge.

It hurt, and she felt disoriented as an annoying ringing sound started up. But if he wanted to fight, she could fight. Not caring that she was only wearing her undergarments, she leapt up and kicked him in the chest, and he went down.

But his leg was already moving, sweeping hers out from under her, causing her to fall as well. Once both were on the floor, they began smacking and punching each other as hard as they could, soon splitting lips and causing nosebleeds.

Zim watched in shock as the siblings fought with each other. He knew their relationship was one of love-hate, but didn't expect them to ever come to blows with each other. He rubbed his stomach as he stood, considering breaking them up. Then he decided against it.

"Gaz, I should go," he said, gathering up his clothes.

"Zim, wait!" she started to call, but he had already fled the room.