Ben and Rook were on their way back to plumber headquarters after having finished their latest mission. However, neither of them was satisfied with how the mission went.
It's all your fault! If you had destroyed Trumbipulor's rat army faster, he wouldn't have gotten away with the alien tech he stole!" Ben exclaimed.
"At least I did not accidentally turn into one of the smallest aliens in existence , a Galvan, to fight a giant alien." Rook exclaimed back.
"You know I can't control what the Omnitrix transforms me into, so that's not my fault."
"Whatever. Let us get back to plumber headquarters so we can file the report." Rook said hastily.
When they got back, they were immediately confronted by Max at the headquarters.
"Guys, I have some good news for you." he said.
"What is it, grandpa?" Ben asked.
"Due to your poor teamwork recently I will include a new temporary member in your team."
"What?!" The partners were confused.
"Grandpa, we don't need anyone new. We just aren't getting along because fuzzball over here couldn't fight right!" Ben exclaimed mockingly.
"It is not my fault!" Rook fought back.
"That's enough out of both of you!" Max said, stopping the fight. "Your team will consist of 3 members until you learn to work together again."
"Fine. So where is he?" Ben asked, feeling defeated.
"Here she comes right now." Max answered.
A short, 10-12 year old-looking girl entered the room. She had long, dark blond hair which was pointy at the back and strange dark violet eyes. She was wearing the usual plumbers uniform except she didn't seem to be carrying any weapons. Both Ben and Rook's eyes widened when they saw their new partner.
"Is...is that it? You want a human kid to join us?!" Ben said surprised.
"I am sorry Magister Tennyson, but we already have one on the team." Rook was talking about Ben.
"Hey!" Ben exclaimed.
The new member stood there in silence. Her face didn't move at all, she seemed deep in thought while staring at Ben and Rook.
"Believe it or not this little fellow was at the top of her class at the plumber academy and graduated earlier. Her results even beat yours, Rook."
The partners looked at the girl in surprise and she looked like she snapped out of her thoughts.
"Hello, um, I really hope I won't be a bother while I'm on the team."
"Do not worry miss, it is no problem. I am Rook and this is my partner,-"
"Ben Tennyson, hero of the Earth, saved the universe a couple of times, nice to meet ya." Ben interrupted.
"I know all about both of you, everyone from the academy talks about your flawless team and how you keep saving the world." The girl replied.
"I'm sure you guys want to talk and introduce yourselves, but it seems like you'll have to do that on your next mission. It looks like our friend Khyber is back in town." Max interrupted.
"Oh yeah, it's hero time!" Ben shouted.
On their way downtown the partners asked each other some questions.
"So, erm, miss, you never told us your name."
"Yeah, and more importantly, how did a human manage to get better scores than all the aliens at the academy? And why aren't you carrying any weapons?" Ben continued.
"You can call me Jess for now. And as a matter of fact, I'm not entirely human, I just don't show my alien half often." She explained. "Also, I got better scores than the others at the intellectual tests, I failed the combat classes."
"What? So you don't know how to fight?" Ben said, shocked.
"No, I don't, but if it makes things better I've won all my battles without needing to fight before." She said reassuringly.
"Exactly how does one win a fight if he does not fight?" Rook asked curiously.
"Teamwork." With that one word, the conversation ended. Normally, Ben and Rook would talk to each other but since there were no other seats, Jess was sitting between them so that wasn't an option. Soon after, they arrived at the place pointed out on the truck's GPS system. It was an abandoned and empty storage place, next to a weapon factory. However, there was no sign of Khyber anywhere. Everyone got off the truck and walked inside, when suddenly they heard the door at the back closing. Then they realized the lights weren't working.
"So you've arrived, Tennyson." A familiar thick-sounding voice came from somewhere inside. It was Khyber.
It was too dark to see anything. Suddenly, they saw an explosion upwards. The roof was blown off and thanks to some moonlight they could see the enemy clearly.
"Whoa, what happened?!" Ben and Rook looked back and saw their new partner was holding a few grenades.
"Where did you get all of that? You were not carrying any weapons before." Rook said curiously.
"For the record, I didn't take any weapons from headquarters because I didn't like any of them. Since we're right next to a weapon factory, I took a few grenades before we came here because I figured I'd need a weapon for the battle." Jess explained.
"Very perceptive of you, you managed to evade one of my traps. Now evade this!" Khyber sent his mutt to attack them. He whistled and it turned into a Crabdozer. Ben and Rook jumped out of the way but Jess didn't move.
"Get out of the way!" Rook yelled.
"Oh calm down." She answered. The alien charged at her when she suddenly disappeared.
"She...is gone?" Rook asked.
"Wrong. I'm still here." She appeared in the same spot she was before. "I just went intangible."
"So does that mean you're half..." Ben asked.
"Necrofriggian? That's right." She answered.
The creature turned to attack Ben.
"Alright omnitrix, gimme something good..." He said.
He slammed the omnitrix and transformed into Armadrillo.
"Works for me." He said. He tried to stop Khyber's mutt but it knocked him into the wall, destroying it. In the meantime, Rook charged at Khyber. He changed his weapon into a sword and slashed right at the huntsman. Khyber dodged it to the left and tried to punch Rook, but Rook grabbed his arm and kicked him back. Khyber recovered and whistled and his mutt turned into a sandworm alien, Armadrillo's predator. Ben was being attacked by it continuously until the omnitrix timed out. He didn't have time to turn into a new alien because it attacked him right after, when suddenly it froze and Jess appeared in the air.
"Do it now!" She yelled.
"Alright, it's time for some Humungosaur!" Ben slammed the omnitrix and this time turned into Crashopper.
He jumped towards the sandworm and kicked it, knocking it down. Rook was still fighting with Khyber when he saw him turn towards Ben. Just as the huntsman was about to whistle, Rook fired some sort of green goo from his weapon towards Khyber's face, making him unable to whistle.
"Lepidopterran secrete, the stickiest stuff in the galaxy." Rook said. Suddenly, they saw a green smoke filling the place. Khyber's mutt had turned into a Buglizard and let out the gas. Rook activated his suit's gas mask but Khyber shot him out of nowhere, and punched him afterwards, knocking him towards Ben who had just turned back into a human. Jess tried to freeze Khyber, but he saw through her intangibilty using his suit's mask and kicked her towards the wall, knocking her out.
"This is the end of the line, Tennyson." Khyber said, as he pulled out a giant blaster he had hidden. Rook stood up in front of Ben. "That won't have any effect on my proto suit." He said.
"On the contrary, this is a particle cannon, it will penetrate your suit and erase you from existence." Khyber said threateningly.
"Ben, anytime now." Rook said nervously.
"I'm trying, the gas made my omnitrix stop working!" Ben said.
Khyber and his mutt had the cornered.
"It is set up to only destroy organic life forms, so your omnitrix will stay with me. Now prepare." Khyber said as he aimed his blaster at them.
Just as he fired, Jess appeared right next to them and pushed them out of the way, letting the cannon hit her. It blasted a hole right through her and she fainted.
"No!" Ben yelled.
"What an unnecessary sacrifice, trying to struggle after you've already lost." Khyber said, preparing to fire his cannon again.
However, something happened. Jess' body started moving again. She stood up with a smile on her face."
"Gotcha." She said. The hole in her body started filling up with a grey liquid, then completely got restored. "You guys were so easy to fool I almost can't believe it."
"Wh-what's going on?!" Ben exclaimed.
"Huh?! How are you still alive, you pest!" Khyber said angrily.
"Alive is an interesting word to use in our situation. My species is never truly alive. The reason I'm talking to you right now is because it's nighttime." She said calmly.
"Then it is as I suspected." Rook said calmly. "You are not half Necrofriggian. In truth, you are half Ectonurite, a rare hybrid might I add." Rook explained.
"Then what about the freezing? You totally froze the mutt a few times!" Ben said.
"I used a small ice blaster from headquarters which I hid in my suit. Also, I'm half human so even if I tried I can't regenerate again." She said.
"That's too bad, little girl, because now you can't save your friends again." Khyber said mockingly.
"That's fine, I don't need to." She answered. "Because now I can fight using my real powers."
Her eyes glowed brightly as the extended one of her arms, which turned into a long tentacle, snatching away Khyber's cannon. At that time, however, the mutt attacked her. She quickly extended her other arm which turned big, tearing through her skin and revealing big claws. She slashed at the creature, which recovered and let out its gas. Khyber attacked her from behind when saw a purple eye on her back. She dodged without turning around, after which she grabbed him and smashed his blaster on his head.
Khyber's mutt grabbed him and let out the gas, managing to escape.
Ben and Rook walked up to Jess.
"Whoa, that was amazing! Why didn't you tell us you could do all that?!" Ben asked excitedly.
"There is nothing amazing about it. I have to leave now." Jess said while looking somewhat sad.
"What?! Why?" Ben shouted.
"Allow me to explain. After Vilgax's planet was conquered by Ectonurites led by Zs'skayr, they are defined as evil, war-seeking aliens and by the Plumbers code are not allowed on planets outside of their own system. Therefore, Jess cannot stay." Rook explained.
"But she's not evil! She proved several times that she's good and a fully-fledged plumber! It isn't fair." Ben said.
"He's right. You can't trust me. I'm going to turn myself in immediately after this. Let's do this again sometime. Oh, one last thing. Promise me you'll always be a team." Jess said.
"Of course." Ben and Rook said together.
Jess flew off in the direction of the headquarters and Ben and Rook got back in the truck, not saying a word and thinking about the friend they'd made and lost over just one mission.
"Ben?" Rook asked.
"Yeah, Rook?" Ben answered.
"I wanted to apologize for our argument earlier. Let us never argue again." Rook said.
"Yeah, I'm sorry too. You're a great partner." Ben said happily.
"Same to you, partner."