Mirai Bulma was busy dismantling and putting away the devices she used to open the time portal. "Hope they made it back safe and sound," she said to herself.
"Mother, I'm sending Obasan ChiChi back in a while," Trunks said. "Do you need any help in the meantime?"
Bulma looked at the mess around her. She could take care of that. She knew what everything was and where they belonged. Trunks didn't. That supermainframe (it can both do many concurrent processes and do them fast) however, needed moving. And the isolation room she set up for #17 and the others needed dismantling. "Yeah," she said. "I need you to move that computer over there, and then dismantle the isolation room." That was one of the advantages of having a Super Saiyajin around the house, Bulma thought, other than the fact that they can also be handy for saving the world from powerful evil enemies.
"Sure thing, Mom," Trunks said. He went to the huge computer and pushed a little button at its side. The machine instantly encapsulated. He picked up the capsule and flipped it in the air once casually before catching it in his hand. "Where do you want me to put it?"
Bulma put her hand on her forehead. "Duh. How could I have forgotten that?" She smiled at her own absent-mindednes. Maybe her age was beginning to catch up after her. "Set it up over there," she said, pointing to the cleared area next to her desk where she worked most of the time. Trunks obediently decapsulated the computer and proceeded to connect the wires to their proper sockets.
When he's done with the computer, Trunks walked over to the isolation room. "Is it safe to dismantle now?" he asked his mother. Bulma checked the screen on her computer. "It's been over an hour since the portal closed, so it should be safe. And there's no energy reading around the room, which indicates that the space-time around this area has stabilized to normal. I should be able to detect a huge energy emission otherwise," she said.
Trunks nodded and went to the isolation room. Just as his mother said, the conditions have stabilized. When the portal opened previously, there had been some heat and light generated. Bulma had to let it subside for a while before letting their visitors from the other timeline enter the portal. It looked quite safe now. He promptly encapsulates the room and walked toward his mother. Holding the capsule between his thumb and forefinger, he was about to hand it over to her when it suddenly burst out in an explosion.
Bulma screamed and shielded her face. However, she noticed the familiar sparks of light that appeared when a portal was opened. "Trunks, get away from there!" she screamed as she ran to her computer and tapped furiously on the keyboard. "How could this have happened?" she thought. "I couldn't have made a mistake."
Trunks noticed the sparks of light too. He also noticed something else. Ki. A very strong one, and it felt distinctly ...evil. He could feel it, coming from the center of the explosion, even as a portal was beginning to form. "No way am I going to let some evil being destroy my world again, just as we're beginning to rebuild our lives," he thought angrily. He turned Super Saiyajin and tried to use his ki to close the portal, or at least hold it off until his mother could figure out what was wrong. Whatever was at the other side of the portal was persistent. He could feel the ki becoming stronger. The thing was very determined to get out, and Trunks had no intention of letting it. He powered up to Super Saiyajin level 2. Even then he could feel the portal growing larger, as if being forced open from the other side. He concentrated on using his energy to stop the portal from opening. Trunks realised he might not be strong enough, even as a level 2 Super Saiyajin, to fight the being inside that was trying to get out. All he could do now was try to patch up the ever growing portal and hope that his mother could do something to close it soon.
Bulma was typing furiously on her computer. Her mind was on overdrive, as all sorts of possibilities entered her head. She's got to find a solution, fast. Trunks clearly doesn't stand a chance against whatever it was at the other side of the portal. He was using all his energy just to keep the portal from growing. If the thing on the other side managed to get out, he would be too weak to fight it.
Figures flew on her monitor. Just as suddenly as that happened, the screen went 'hang'. "Dammit!" Bulma threw her fists on the keyboard. "This isn't the time to crash!" she yelled in frustration. Then she noticed the smell of burning wires. The computer made some 'bzzt' noises. Smoke came out of the machine and the screen went completely blank. The room was overheating from all the heat generated from Trunks, the portal and the mysterious being at the other side. Bulma realised that the other equipments in the lab would have been damaged by the heat too. And that means that there was nothing she could do to help her son.
She looked helplessly at him, still holding on desperately with every ounce of energy in his body. But even Bulma could see that he was losing the fight. Then she heard him shout "HAAAA!!!!!!" as he aimed a huge Kame Hame Ha at the portal. She couldn't see anything in the resulting explosion. The room shook violently. When the smoke cleared there was no sign of the portal. Or Trunks.
"No..." Bulma said weakly. "He didn't..." But what other explanation was there? Trunks had managed to close the portal, and push it, together with the being inside it, back where it came from. And, it seems, he had gotten himself pulled in together with the portal. He's gone.
ChiChi ran into the lab when she heard the explosion, to find Bulma kneeling on the floor, pale as a ghost. She went to her. "What happened?" She looked around at the damaged lab. "Where's Trunks?"
"He's gone," Bulma said said it calmly, but she was on the verge of histerics. "And he's never coming back." She let herself fall into ChiChi's arms and wept.
Next: #17mania, Trunks vs. Piccolo and Great Saiyaman saves the day!