Mirai Bulma stared at the group of 6 in front of her. Even after what her son had told her in advance to prepare her, she was sitll shocked. Right there in front of her stood the evil android #17. Well, he's not evil anymore, she reminded herself, though she couldn't help but feel nervous being so close to him. And the children... This Trunks looks just like her son, though his features were not hardened by years of suffering. And Bra was so pretty! Just like her when she was that age, she thought (vainly ^_^). She smiled to think that in another timeline she and Vegeta would actually get married, settle down and have another child together.
She smiled at the other children in the group. Goten really looked just like his father. If he'd had the same hairstyle she wouldn't have been able to tell them apart. Pan the tomboy, was Gohan's daughter, and Marron! She couldn't believe it when Trunks told her that Kuririn had married #18. Well, here was their daughter right in front of her. She certainly looked a lot like her father, and had her mother's hair and figure.
"Welcome! Come in," she welcomed them in after she got over her shock. Trunks and Bra couldn't help staring at this woman, who in this timeline was their mother. She did look like their mother but older, even though she should be younger. She was just as beautiful nevertheless.
Soon, everybody settled down and made themselves at home. They had a small dinner (by Saiyajin standards, because Bulma had enough only to feed 1 Super Saiyajin). But other than that everybody was happy as they traded stories. Bulma and Trunks' guests told them about Majin Buu and how Goku had been able to live again in their timeline. Mirai Trunks told them about his life and what happened after his trip to the past. Trunks and Goten listened attentively. They didn't believe it when Gohan told them the story when they were little, until they'd seen his world for themselves. And here they are face to face with Mirai Trunks himself. The girls just listened open-mouthed, as they've never heard anything about this before. #17 loked uneasy being in a world where the counterparts of himself and his sister had caused so much suffering. But Mirai Bulma went to him smiled to him. "I understand you and your sister were as much victims as we were, #17," she said. "But I'm glad you're able to have freedom and happines in your timeline. Your niece seems to adore you." She looked at Marron who was still hanging on to Mirai Trunks' every word. #17 followed her gaze and smiled. He adored his niece too. And he was amazed that Mirai Bulma and Mirai Trunks could still be kind to him even after all that his alternate counterpart had done to them. He smiled back at her akwardly.
It was late at night when they finally addressed the problem at hand, namely how to get their guests back to their own timeline. Pan and Bra werre asleep upstairs while the rest of the group discussed their situation in Bulma's lab.
"Portal-based time travel device, huh?" Mirai Bulma said. Goten and Trunks told her what little they knew of Gohan's and Bulma's project and how the device suddenly opened a portal that just sucked them right in.
Mirai Bulma was thoughtful. "My initial experiments were based on such concepts too. But I decided that using portals was too dangerous as it was very difficult to control their size and how long they can stay open. They also tend to suck other things in the vicinity into them. Which was what happened to you all. Actually, time travel in itself is very dangerous no matter what method you used as any little act you did in the past could change the future in unpredictable ways, effectively creating new timelines like yours. That's why the number of time travellers should be minimised, and that a time traveller should minimise his contact as much as possible with the other worlds he visits." She looked meaningfully at her son, who smiled sheepishly. "Which was exactly what my son DIDN'T do. I told him to just give the medicine to Goku and leave immedeately, not go and destroy Freeza's fleet then stay and chat with Goku and your parents. He could easily have nullified his own, I mean yours, Trunks (she pointed at Trunks) existence! And then--" "Well, they're here now, so no harm done," Mirai Trunks managed to cut in. Mirai Bulma glared at him for interrupting, but smiled again. She couldn't really stay mad at him for long. And she had no way of knowing that just giving Goku the medicine wouldn't have changed their own timeline. It was only after Trunks returned from his first trip to the past to their own world where nothing changed that she realized that her theory about alternate timelines was correct. What nobody knows now is what the effects of new timelines would be. If there are an infinite number of universes that can be created from time travel, what will the effects of crossovers be? Will it cause them to eventually converge into one? And what would be the effects of that? The possibilities are incalculable. Bulma could just imagine all the versions of Freeza, and Gokus who never bumped their heads, and Vegetas who never lost to Goku, not to mention Gero's cyborgs and all the enemies they've encountered in the past. "Anyway, time portals are very dangerous. Not only that, they are highly unstable and waste a lot of energy."
"That was why I constructed the time machine. With it I could ensure that only the intended traveller gets to travel to the past. Or so I thought," she said, remembering Cell.
"I don't suppose you could send us back one by one using Trunks' time machine," Goten said.
"I'm afraid not." Mirai Bulma said. "The machine takes approximately a year to recharge after a two-way trip through timelines. It takes too much resources for even 1 trip and we're rather low on resources here. And 6 trips through timelines will definitely exhaust the machine. It wasn't designed for more than 2 trips."
"What about the one Cell took?" Mirai Trunks asked. "I think I left it in the past since I can't find it anywhere here. With it, we'll just need 3 trips. I'm sure you can modify the machine for one more trip."
"Umm.. that machine was accidentally destroyed when we cleaned mom's old capsules..." Trunks said, exchanging a quick glance with Goten.
"So what can we do?" Marron asked.
"Looks like we'll have to stick to portals," Bulma said. "I may be able to construct a safe portal opening device to send you back home. I still have the blueprints of my early experiments. But calculating the exact timeline and designing and building the device will take some time, a few days at least." She looked at the tired faces around her. "You all look tired. I suggest we call it quits for today." Everybody agreed and they went to bed for the night.