Long ago, two races ruled over Earth: HUMANS and MONSTERS.

One day, war broke out between the two races.

After a long battle, the humans were victorious.

They sealed the monsters underground with a magic spell.

Prologue

Many years later in a different dimension...

It was a bright and sunny day in Gamindustri. Neptune and the other CPU's were playing a game together in the Planeptune Basilicom. The CPU candidates were also there, playing on their handhelds. Suddenly, Histoire, IF, and Compa walked in the room.

"Pardon everyone." Histoire said. "The meeting shall begin soon."

They all nodded and got up. As they started walking to the conference room, Neptune broke the silence. "So, uh… what's this meeting about, again?"

"Do you ever pay attention?" Noire asked angrily. "It's about that abyss on Mt. Ebott that got discovered last week."

"Oh! That thing!" Neptune replied.

"I had gotten intel that some strange noises could be heard coming from inside." Vert added.

"Ooh spooky~" Neptune said.

With that, they entered the room and sat down around the table.

"As you are all aware, I called all of you here to discuss the strange abyss found on Mt. Ebott last week." Histoire said.

"Apparently it has some sort of magic that creates a barrier around it." IF added.

"So we can't go in it?" Nepgear asked.

"According to my information, it is quite possible to enter, however, it's said that no one who has gone in has gotten out." Histoire explain.

"So you're saying we should go investigate?" Blanc asked.

"It would be foolish of you to do so. I have sent groups to attempt to destroy the barrier before anyone enters it." Histoire replied. "However, I will be sending you to aid in as much you can with it. Good luck."

"Alright! You guys go do that while I-" Neptune was cut off by Noire grabbing her by the ear and dragging her out.

"Oh no, you're coming too, you know?"

"NYOOOOO!" Neptune yelled as she was taken prisoner to Mt. Ebott with the rest.

Later

"So… this is Mt. Robot?" Neptune said curiously.

"Mt. Ebott." Noire responded annoyed.

The CPU's and Candidates had arrived at the summit to investigate the abyss.

"So. What do you think could be at the bottom?" Vert asked.

"I dunno. Probably some spooky ancient dragon monster boss or whatever." Neptune replied.

"It's probably just nothing. Not like I'm gonna find out though." Noire added.

"Hey guys." Neptune said. "Wouldn't it be funny if I just tripped on something dumb and-"

"Neptune! Wait!" Nepgear yelled.

But it was too late. Neptune found herself already tripping on a branch and falling into the abyss.

"WAAAAAAAAHHHHH!"

"Oh you have got to be kidding me." Noire shouted.

"NEPTUUUNE!" Suddenly, Nepgear ran and jumped into the abyss… for some reason. What she was trying to accomplish, I don't know, but she did.

"WAAAAAAAAAAAAHHH!" They both yelled as they fell to their probable death. The whole group was left staring in disbelief at the entire thing.

"Wh-WHAT JUST HAPPENED?!" they all shouted.

Let me know what you guys think of my first fanfic. I always thought Neptunia and Undertale had a ton of similarities and I was kind of surprised that there's barely any crossovers between the two. I hope you enjoy reading it. This will likely be a pacifist route crossover so don't expect any bad times in the main story. Anyways, hope you enjoyed ;)

P.S. Chapters will be longer from here on out.