Chapter 1: A Year Later...

The nation of Planeptune. Over the past year, it has flourished, and yet... it was filled with a silent air of sadness. Everyone felt it, and they all knew why. They had lost their beloved Candidate, Purple Sister Nepgear. And they knew that no one felt that more than their own goddess, CPU Purple Heart, also known as Neptune, who was once Nepgear's older sister.

Deep down, everyone wished that Neptune would once again find happiness. But as time went on, they felt like it would never happen...

Despite all Neptune had done to make their nation prosper, she had not been seen leaving her home and Basilicom, Planeptune Tower.

Above the city, something, or rather, someone soared high in the sky. It was too high for people to make out who it was. They could only see it as a white star. But they knew who it was. This had become such a common occurrence, it wasn't long before it came out who it was.

Flying towards Planeptune Tower, a transformed CPU with long, flowing white hair, wearing a black swimsuit-like outfit with arm-length gloves and thigh-high boots, her blue-green eyes focused on her destination.

As Black Heart made her descent onto the tower's balcony, she took a deep breath. Here we go again, she thought to herself. Upon landing, she turned back into her human form, Noire.

Knowing she was probably expected. In the past, Neptune had tried to turn her away, but nowadays, you couldn't ignore visitation from another nation's goddess, so she just let her come in. As such, the twin-tailed woman could walk right into the main living area of the Basilicom, which she did.

Histoire was standing, well, hovering around, when she noticed Noire come in. "Ah, Noire, I see you're here again."

"Well, you know, Neptune needs someone to cheer her up," Noire replied.

"She does appreciate your company. Though you have been coming over more frequently as of late. Are you sure that your nation won't be hurt by this?"

"My Shares are fine," Noire said calmly, referring to the energy given to goddesses by the faith of their people. "I do plenty to keep my nation prospering. Besides..."

As Noire trailed off, Histoire got worried. "Noire...?"

"It's... nothing you need to be worried about," Noire replied. "What matters right now is Neptune."

Histoire sighed. "Good luck." Noire nodded as she left for Neptune's office, and once she was gone, Histoire said quietly to herself, "though, at this point, I don't know if anything can change. Not since what happened a year ago."

Neptune was in her office, doing paperwork. She was quiet, her thoughts to herself. Very much unlike how she used to be, but it was the norm for her now.

When she heard a knock on the office door, she stopped. "Come in."

Entering the room was Noire. "H-hey there, Neptune."

"Oh, hey, Noire," Neptune said softly.

"So, how are things going?"

"Oh, just working. I've got to keep my people happy, after all."

"Are you going to be taking a break soon?"

"No. I can't do that. I'll have a meal or sleep, but I can't stop otherwise, or else everything will go wrong."

The hurt Noire. Sure, it was important as a goddess to work, but this wasn't like Neptune. She was supposed to lazy, just wanting to goof off, play games, and hang out with her friends.

"...Neptune, you've got to take a break sometime. Not even I work this much," Noire told her.

"And go back to the lazy me that let my nation fall into disarray time and time again," Neptune responded, with little emotion in her voice.

"Look, even I have been pretty lazy at times, and I still get my work done. Besides, this isn't you. Come on, let's go play some games!" Noire said, trying to sound enthusiastic.

"Well, if you want to, the console is in the living room. Enjoy yourself."

"Really, by myself? Aren't you always calling me lonely and claiming that I have no friends. Because right now, you're the one with no friends!"

Neptune looked up, an annoyed look on her face.

"O-okay, so maybe that a little harsh," Noire admitted. "But really, you keep pushing us away. I know your hurting, and I want to help you."

"LIKE HOW YOU HELPED MY SISTER!" Neptune snapped.

"Neptune..." Noire said quietly.

"Even I couldn't save her! All I wanted to do was laze around have fun. And because of that, I lost the one person I loved the most!"

"Neptune, it wasn't your fault..." Noire continued, still quiet.

"Was it? Do YOU know why she's gone? If I was there for her, then maybe she'd still be here. But no, I had to play some games instead, while she went off on a quest. Alone." Neptune started tearing up as she said that, before telling Noire, "please go. I need to finish this by the end of the day."

Noire was saddened by this, and turned to leave, tears in her own eyes.

How could she have let this happen? Why didn't she act sooner?

When the CPUs told Neptune it was time to stop looking for Nepgear, and that she wasn't coming back, it was hard. They didn't want to do it, they still wanted to find her, but with no evidence as to what happened to her or where she was, everyone realized it wasn't likely they'd find Nepgear, and they had to convince Neptune of that. It was for her own good.

After the fact, everyone decided to leave Neptune alone to grieve, and Noire... simply went back to work. She was saddened by the loss of Nepgear, but chose to not worry about it. She wasn't her sister, after all...

And eventually, Noire enjoyed the peace and quiet. Not because Nepgear was gone, but because Neptune wasn't bugging her. She was always coming over, annoying her, being a nuisance. It was nice not to be bothered.

But after about a month, Noire... started to feel lonely. Her sister, Uni, wasn't talking to her, which was its own problem, but moreover, it just... wasn't the same without Neptune. Noire missed her smile, her cheery, friendly attitude. Even if it annoyed her in the past, Noire missed it, and she wanted that part of her life back.

So she went Planeptune, to visit her friend after so long and see how she was. And what found... a Neptune who wasn't herself, nearly emotionless, doing work and refusing to take breaks and enjoy herself. She didn't even want to see Noire, though, after a while, she let her stay around, so long she didn't bug her.

But it still bothered Noire to no end that this is what had become of Neptune, of the goofy moron she used to know. So Noire made it her goal to bring the old Neptune back, the real Neptune.

As the year progressed she'd come over, again and again, trying to get Neptune to take a break, play some games, go eat out. She even tried to make her laugh. It started out her coming over about once a month, then twice a month, then once a week. Noire still made sure to do what she needed to keep her nation prospering, but more than half of her free time was spent trying to bring Neptune back to her old self.

And all of it... to no avail.

And now... Noire wondered... what if she had tried earlier? What if she was there for Neptune, and had been her shoulder to cry on. Would things have been different?

Noire was still shaken. This had been the first time Neptune had snapped at her. And now she didn't know what to do.

Noire wished the other goddesses would help, but they didn't seem bothered by what happened to Neptune. Sure Vert, seeing as she was close to Nepgear, was distraught by her disappearance, but wasn't seemingly worried about Neptune. And Blanc, she just didn't care. She just happy with the peace and quiet, like Noire had been, but that the extent of it. She'd get no help from them.

As these thoughts swirled in Noire's mind, and reentered the living room, and found Histoire still there.

Histoire...

Noire anger flared.

"Are you happy now!" Noire snapped at her. Histoire spun around in surprise while Noire continued. "Neptune a hard worker now, at the cost of the rest of losing an important friend!"

"Noire," Histoire responded, getting her bearings. "Please calm down."

"No! Neptune won't even THINK about leaving her work. I know the goddess's duty is to their people, but does it really have to be at the cost of who we are!?"

"Noire, I didn't want this either!" Histoire shouted back. After that, the two fell silent. Once they were calm, Histoire continued, "yes, I wanted Neptune to be a responsible goddess and do her work, but not like this!"

Histoire turned to face the window, and continued. "I've been recoding Gamindustri's history for a long time, and when it comes to Planeptune... our last goddess, Uranus, died fighting the Deity of Sin, along with the other goddesses of the last generation. Before her, there was Uzume, who had to seal herself away because of the peoples' perceived distrust over her abilities. And yes, she is back now, but it still haunts me about what happened to her. And before her... almost every goddess of our nation has died, either from war with the goddesses of their generation or from protecting the nation from a major threat."

Noire was crestfallen. She never knew Histoire had suffered so much.

"I thought, with Neptune, things would be different," Histoire continued, "she's overcome every obstacle in her way, befriended all of the other CPUs of this generation, and saved countless lives. I thought she'd usher in a new world of peace, and still live to see it. Even if she was an incredibly lazy leader."

"But then we... SHE lost Nepgear," Noire summed up.

"Yes, someone who was deeply important to her. When you look back, Neptune has always saved those she cares about, Uzume, Peashy, and all of her friends. But when it came to her sister, whom she loved more than anything, she couldn't save her. And that loss has hurt her more than anything else would have otherwise."

"Do... do you ever think she will go back to her old self?" Noire asked.

"I don't know... who Neptune was before was always the person we knew her to be, even before Nepgear was born. But once she was born, she became central to Neptune's life. Even when Neptune was... let's say, less than kind to her, she loved Nepgear. Without her, I don't know if she'll ever be the same again."

"...If only we knew what happened to Nepgear, then maybe Neptune would have some closure."

"If only..." Histoire turned back to Noire. "I know you must be pretty stressed out. Between Neptune and Uni..."

"Do you think Uni believes I'm ignoring her by coming here?"

"I can't say. I know she's been acting this way since you stopped looking for Nepgear a year ago, so that's before you started visiting again. It's hard to say how what she's feeling."

"She's become so distant, and she always gets angry with me."

"She was close friends with Nepgear."

"But I'm her sister! I should be there to comfort her. But she won't even look at me. I doubt she even wants to see me right now."

"I understand. If you want, you can stay here the night."

"Wh-wha- Y-you sure? I mean, I don't want to intrude-"

"It's fine, Noire. Besides, Neptune usually eats her dinner in her office, and I could use some company."

"These really are lonely days, aren't they," Noire realized. "What are we going to do?"

Histoire simply shook her head, having no answer.

Noire was pretty frustrated by this. Between Neptune shutting everything out, and Uni hating her sister for some unknown reason, she felt like her whole life was falling apart.

But, when she thought about it, that's probably how Neptune felt. But what could she do? If Noire couldn't fill the void of Neptune's sister... who could?

As the day turned into night, Noire and Histoire had a relatively good time talking to each other. They spent their dinner talking about the happenings in their nations. It was great for Noire. She loved to gloat about what her nation was doing to advance, and it was a good excuse to keep her mind off of everything else that was going on.

But eventually, the day came to end. Neptune popped out for a bit inform Histoire that the day's work had been finished, and was surprised to see that Noire was still around, but brushed it off and went to bed, which did not help Noire's mood.

Histoire provided her a guest room, and Noire went to sleep. Or at least, tried to.

She couldn't rest. It had been like this for a while. She couldn't stop thinking about... well, everything.

Eventually, she decided to get up. Maybe if she got some water, she'd feel better.

As she got into the kitchen and turned on the light, she stopped in front of the fridge.

Did Neptune even eat pudding anymore? Maybe if she made her some-

Suddenly, she heard something behind her. Turning to find it, she was shocked by what, or rather who she saw.

At first, she thought she looked familiar, but on closer inspection, she wasn't anyone she met before. But still, she looked a lot like...

Trying to get a better look at her, this girl had purple that was grown past her shoulders and near her mid-back, and purple eyes on a face full of innocence and curiosity. She was about the same height as Uni, and well, she had the body type as Uni too, petite with a smallish chest, and she was clothed only in a simple white dress and was barefoot.

This girl... Noire thought. She couldn't be-

Her thoughts were interrupted when the girl said the most asinine thing.

"Are you my big sister!?" she asked with excitement.

Author's Note: Before you ask, no, this girl is not Noire's sister. I'll get more into her in the next chapter when she's further introduced.

And in case you didn't figure it out, it has not been a year since Nepgear disappeared. It has been a year since they stopped LOOKING for Nepgear, and 15 months since Nepgear disappeared. Just so you know.

Now, while I talk more about this new girl next chapter, I'll talk about how she fits into this story, and how I came up with this story in general. Basically, since joining this fandom, and starting to read other's fanfics, I've seen lots of stories when people write in little sister OCs for the goddesses. I've seen some for Vert (which should surprise no one), one or two for Plutia, and even a couple for a fully-realized CPU Nepgear.

But the ones that really inspired this were ones where they give an extra sister to the goddesses who already have one. I've seen one for Blanc (which, I'm going to be honest, she already has twins for little sisters, does she really need another?), and one for Noire (which I actually mentioned in the Author's Notes in my Solgear story, just not in the context of its main plot).

Basically, I decided to give Neptune a slice of the pie, but not exactly in a fun way. This plot idea is actually very much inspired by the Noire's-new-sister story I mentioned (which is called "Second Chance Sister"), where Uni is killed, and later on, a new Lastation Candidate is born to take her place (the author recently just started a rewrite of this story). Another part of the idea also came from Nanya's "Shadows of the Heart", just in reverse.

Now, in the case of this story, I choose to make it a mystery as to what exactly happened to Nepgear, hence her simple disappearance. You'll have to wait and keep reading as I put out new chapters to find out.

Here's a list of many of these sister OC stories I mentioned, at least ones I remember, because they were interesting to me (all of which are here on Fanfic):

- "Green Sister" by YuriLover567

- "A Verdant Breeze" by YuriLover567

- "Iris Sister" by The D.U.N.K.666

- "Shadows of the Heart" by Nanya

- "Hyperdimension Neptunia: Solia's Journey" by MechaKingGhidorah100

- "Hyperdimension Neptunia Third Sister Light" by Somedudeonline

- "Second Chance Sister" by decode9

- "Second Chance Sister ReBirth" by decode9