Dragon Ball Super: Another Warrior from another World

Introductions

"Come on, Goten! We gotta find out what that huge spike in power's from!"

"I know, Trunks! Maybe that could be a strong baddie that needs a lesson!"

Goten and Trunks' day has just become a little more interesting.

Earlier, the two boys were going out to find a wedding gift for Goten's older brother Gohan and his soon-to-be-wife Videl. Initially, they decided to get a diamond ring but found none that they thought would suit Videl. Next, Trunks suggested a bottle of skin toner but found out that all were out of Goten's pocket money budget. After overhearing an elderly man about spring water that makes "wrinkly old bats become smooth as silk"(old man's words, not theirs), they decided to collect some of this spring water as Goten's wedding gift for Videl.

After collecting their spring water and fighting off a giant snake, the boys are on their way to deliver their new gift to Videl at her home. On their way back, however, they both sensed a massive surge of energy nearby and decided to divert to investigate the massive source of energy.

Currently, they're flying up the path of a river where the massive energy comes from. Not long after, they can see what looks like a house up ahead and land a distance away from it, quickly hiding behind a rock formation and lowering their ki levels to mask their presence.

"That must be where that energy comes from.", said Trunks.

"Yeah, but who lives there? I hope we won't face anyone bad like Majin Buu.", Goten nervously added with a gulp.

"I hope not. But if this guy really is strong and evil, I'm sure Dad and Goku will save the d—!!", Trunks started, but saw something, or more specifically someone, at the corner of his eyes and pointed at the person, "Goten, look! That must be where that energy spike is from!"

Goten looks at where Trunks is pointing and his eyes widen as he whispers, "Is..Is that Dad....?"

Both boys see a man on top of a large rock formation near the house they saw just a moment earlier. His black hair spiking up and his orange gi ruffling as he looks to be powering up, his ki levels increasing. Both boy's shock only escalates further when right in front of their eyes, the man unleashes an almighty roar with his black hair turning gold and the air around him explodes, after which he punches the air above him.

"That man is a Saiyan and he's a Super Saiyan as well! But I thought Goku, Dad, me, Gohan and Goten are the only Saiyans alive?", thought Trunks in his head.

Goten, meanwhile, is very much confused about what's happening.

"But I thought Father was ploughing the field back home? If Mother finds out Father's here, she's gonna be very, very, VERY angry!"

"Hey! Who are you two?!"

"AAAAHH!!"

Both boy's thoughts are interrupted by a female voice coming from behind, and they both scream and jump up in fear. Battle instincts coming immediately, they turned around and took a battle stance, before both their faces took on a blush.

Standing before them is a teenage girl nearly a foot taller, wearing a black sports bra and blue gi pants with a Jacket wrapped around her hips tied by the sleeves. Judging by her long purple hair clinging to her shoulders and her gi bottoms dripping wet, she must have come out from the river. Her back/blue eyes narrow when she hears no response from the two boys, still in shock at seeing an attractive girl before them.

"Hellooo~~? Bulla to the two boys spying on our father? Is anyone home in there?"

"Hey, sis! What did you find out here?!"