Jeremie and Aelita were back in at the factory trying to figure out who this mystery person on Lyoko was. So far after hours of data mining all they could find out was that it was a girl that carried similar codes to Aelita meaning she could deactivate towers and have access to the information in Sector Five. There wasn't much more information on the girl. Later that day Jeremie decided that he wanted to see if he could find this girl on Lyoko. He told the others to meet him at the factory for an important mission.
"So, what's this all about Einstein?" Odd questioned
"We're going to find this girl that's somewhere on Lyoko" Jeremie stated.
"Do you know where she is exactly?" Yumi asked.
"She's still somewhere in the desert section" He responded. The group minus Jeremie was virtualized onto Lyoko in the desert section. At the moment it seemed pretty vacant. No girl and no monsters. It would make sense that there were no monsters since there was no activated tower. However, the desert section was a pretty open place and fairly small so there should be really no trouble spotting a person. That was if they weren't hiding out in a tower.
"Jeremie, do you have an exact location on where she is?" Ulrich asked. "We don't see anyone here" He then added.
"Hold on, give me a moment" Jeremie spoke as he tried to pin point her location. "According to the data on the map she's Southeast from where your location" He then answered after finding her exact location. "She's currently on the move though so you better hurry" He added noticing that her icon was moving on the screen.
"You mind sending us some vehicles?" Odd requested. Jeremie did as requested and sent them their vehicles. "Hey Ulrich, imagine if this mystery girl turns out to be your sister" Odd joked.
"Shut up Odd that's not funny" Ulrich stated in no mood for his jokes.
"Oh, lighten up will ya" Odd responded then moving ahead of him. Then soon an activated tower appeared on Jeremie's screen. Luckily it was located in the desert sector.
"Guys forget about the girl for now. A tower just activated west for where you guys are now" Jeremie announced. The group abandoned their mission and headed straight for the activated tower. "There's a swarm of hornets and a group of crabs heading your way" Jeremie warned noticing the monsters appearing on the screen. Odd managed to take out two hornets with his laser arrows and Ulrich defeated one crab. Yumi focused on getting Aelita to the tower while blocking attacks with her fan. Then suddenly several of the hornets were taken out at once. Odd had caught up to Yumi and Aelita so they thought it was him who did it.
"Well done Odd" Aelita praised.
"That wasn't me" Odd responded confused to who took out the hornets himself.
"Well it wasn't me or Ulrich. I wonder who did it?" Yumi questioned confused.
"Look ahead of you. It's the mystery girl" Jeremie voiced. The group looked head and sure enough, there she was. She was tall with brown hair that was pulled into a bun with her bangs hanging loose and a black headband that matched the black and green suit she was wearing with silver armor around her chest. She leaped over a crap shooting it in the target with her laser pistol causing the crab to explode. Ulrich immediate recognized the girl. Odd was right, it was his sister.
"I don't believe it. Odd was right. It is her" Ulrich commented in disbelief after joining the others.
"What? I was kidding. I didn't think it would actually be her" Odd noted. After she defeated the crab, she ran into the tower to deactivate it.
"I'll say, she has impeccable timing. She's deactivating towers before XANA is able to launch an attack" Jeremie stated. After the tower was deactivated, she exited the tower and was greeted by the group.
"Umm hello. Who are you guys?" She asked.
"Nina…?" Ulrich called out to see if it was really her or if XANA was playing a trick on him. The girl seemed surprised by that name.
"The only person that calls me that is my little brother Ulrich" She stated in shock. Ulrich then ran up to her giving her a hug.
"It really is you Nina" He said as he embraced her. That's when she realized that it was Ulrich. She returned the hug after it hit her that he was her brother.
"I missed you little brother" She mumbled to him. The two pulled apart. "Sorry, I should probably introduce myself. I'm Katrina Stern, some people call me Trina and only this one calls me Nina" She said as she placed her hand on her brother's head. The group introduced themselves to her and explained to Katrina what was going on. Ulrich was happy that after five years apart, he was finally reunited with his sister. The only problem was that she was stuck here on Lyoko.