Inkopolis

It's afternoon and Callie and Marie are heading back to their apartment out of exhaustion after their legal struggle to adopt Rei.

Bringing out some spare keys, Marie tries twisting it, but was surprised that it was already opened.

"Odd?"

"I guess she's waiting for us." Said Callie.

"Yeah."

After that, the Calamari cousins open the door as they see no one in the living room and the TV is left untouched.

"Rei! We're home!~ Eh?" Callie stops as her smile instantly drops.

Nothing has been touched, not even the bed that's been sorted earlier in the morning, the bathroom is quiet and the kitchen is still colder and the refrigerator isn't being taken.

"Rei?" Callie calls.

"Aori, don't you think that Rei went out of Inkopolis?" Marie turns her head towards Callie.

"How can you tell?"

"Remember what happened yesterday? She agreed to continue, but I didn't expect her to leave already."

After Marie opens her mouth, Callie drops the bags out of shock as her eyes widens.

"Hotaru… What you're saying is…"

"Considering she's gone, that means she's going to get herself hurt, or even worse… Splat." Marie gasps as she realises what Rei is actually doing.

"Then we have to hurry! Gramps knows where she went! Hold on! Let me call through the speaker!" Callie hastily picks out her hero headset as she's starting to call Rei. "Rei? Rei, can you hear me!?"

The speaker is making some strange noises as Rei can hardly be heard through.

[Who… you…]

Implying that Rei can't hear as well.

"Bad connection?" Marie asked.

"Yeah." Callie confirms, leading the duo to hastily leave the apartment as Marie locks the apartment door.

Octo Valley

Cap'n Cuttlefish is relaxing again, but this time listening to a song by those called 'Off the Hook.'

What makes this surprising is that he's interrupted by a shade on top of him.

"Hm? Hello?"

A fist grabs a hold of Cap'n Cuttlefish's rag top and yanks him from his chair, only for him to witness a certain inkling.

"Ah! Oh! Hotaru? I didn't expect to see you here."

"Calm down, Hotaru! We need gramps to answer us." Callie is behind Marie as Marie herself is still holding her grandfather's top.

"I know… But he brought Rei down there without our supervision!" Marie growled.

"I know I made a huge mistake. But she'll be fine." Said Cap'n Cuttlefish as his tone remains positive.

"She may be, unless there's a certain point she'll be reaching." Marie warned.

Cap'n Cuttlefish opens his bulging eyes after he remembers a certain incident. "O- Oh! Then she won't be fine then. What have I done?"

"It's not your fault! We left her alone with our apartment keys!" Callie is also guilty as the same could be said for Marie.

"But fret not! She's only looking for a lassie that looks exactly like her. Hmm… I could've sworn that she was called Zero…"

"Zero!" Marie gasps.

"Hm? What do you mean Zero?" Callie raises an eyebrow.

"Rei called out for Zero after she woke up, but is it true that she looks like Rei?" Marie asks a question as if Zero is also related to Rei.

"I don't know… Maybe they could be long lost twins." Cap'n Cuttlefish assumed.

"Or clones. Either way, we can't let her go that far!" Said Callie, also assuming who Rei and Zero are.

"Yeah." Marie agreed while she and Callie are changing into their hero uniforms like they did yesterday.

"Before you go, I want to say that I'm sorry." Cap'n Cuttlefish sighs.

"No, gramps, I'm sorry. It's because we can't afford to lose another inkling. Daigo is gone and we don't want her to be next in line." Marie sighs out of guilt.

"It's okay. It's normal to get angry over such trivial things. Good luck, Agent 1, Agent 2."

Afterwards, both Callie and Marie super jump towards a similar location where Rei went to, leading Cap'n Cuttlefish to try a speaker.

Then it makes a noise as the connection is worse.

Back to the cave, marching together are the inkling girl trio, Agent 3, 3.2 and 3.7 as they follow the noise through the light.

"Oh? Is that someone fighting an octarian?" Agent 3.7 is curious to know what's through the hole.

"I think it's a fellow Agent. And it sounds like a charger." Agent 3.2 confirms as she checks out.

"Agent 2!?" Agent 3 exclaims with excitement.

"Dunno. But let's find out." Agent 3.2 orders as the trio enters through the hole.

With the trio entering, right in front of them is an arena filled with yellow ink and an inkling in a beanie that covers his eyebrows and nearly his eyes, a yellow high visibility coat that is different to the usual Agent 3 uniform and leggings as if he's covered up except for the hands.

The one sitting down on a dead Octonozzle and holding a zapfish around his arm is an inkling boy known as Agent 3.4.

"3.4!? Why are you here!?" Agent 3.2 is surprised to see Agent 3.4 alive and calm as ever.

"3.4?" Agent 3 asks.

"He's one of us and usually plays solo when it comes down to fighting the octarians." Agent 3.7 answered.

Agent 3.4 sighs as he has his eye on Agent 3 herself.

"Looks like we finally meet, Zero. I know you're behind this inkling, so don't go hiding." Agent 3.4 calls out.

"Huh? Zero… That means she is- !" Before Agent 3.2 answers the truth, in a split second, Agent 3.4 puts his Hero Charger on Agent 3's chest as the inkling trio exclaims in shock.

"Wait wait wait! What's going on!?" Agent 3 is losing the plot after being put at a gunpoint.

"That's what I've been saying! 3.4, what is the meaning of this!?" Agent 3.2 angrily yelled, leading Agent 3.4 to sigh again.

"3.2, 3.7, why are you still protecting Zero?"

"Excuse me? We were with three the whole time." Said Agent 3.7 with a bitter tone.

"Even if you are, I still need Zero. You know what you've been put into, Agent 3." Agent 3.4 is charging his Hero Charger as it causes Agent 3.2 and 3.7 to point their weapons at Agent 3.4.

"I never thought I would have to point a gun at a friend." Agent 3.2 chuckles bitterly as she knows what he's doing to his own ally.

"Same here. Now, Zero, reveal yourself." Agent 3.4 orders.

"Hold on a minute! You got the wrong inkling! I'm Rei, Agent 3!" Agent 3 exclaimed.

"Even if you are, Zero is the one I'm waiting for."

Before Agent 3 makes a run for her life, Zero appears by pushing Agent 3 and standing in front of her to protect her.

"Zero!" Agent 3 gasps with joy.

"So you're looking for me. And how did you know my identity?" Zero asks in a calm tone.

"Ever since three woke up, I know you're talking to her as if you're talking to yourself." Agent 3.4 answers.

"Talking to herself? But Zero is with me this whole time." Agent 3 points out.

"Disappearing in front of me… And you're denying who you are? Hm. I'll be waiting for you to acknowledge who Zero really is." Agent 3.4 sighs and then lowers his Hero Charger. "3.2, 3.7, think about three's behaviour differences. Zero is still near you."

This causes both Agent 3.2 and 3.7 to stare at Agent 3 in shock after realising that a demon in the form of an inkling is among Agent 3.

Looking at the Hero Shot, Zero has found out a micro device beeping on her gun as she's being watched by a fellow agent.

"Zero?" Agent 3 calls out.

"We're being watched. So, Agent 3.4, you're a clever boy. But that doesn't mean you can spy on others." Glaring straight at Agent 3.4, Zero clenches her fist on a gun and furrows her eyebrows while crushing a said device. "Rei, I'd be careful with this guy. Any more stunt he pulls and we'll splat him."

"No. I can't do that." Agent 3 declined.

"If you don't, then I'll do it for you."

Finally, Zero walks forward as she vanishes again, causing Agent 3 to gain some sort of a panic attack.

Agent 3 then turns around, watching Agent 3.2 and 3.7 whispering about Agent 3 herself.

"Um…" Agent 3 is about to open her mouth as she caught Agent 3.7's attention.

"Oh? Three. I see you're worried about us."

"Yeah." Agent 3 nods gloomily.

"It's getting late. Let's camp out here for now. Three, we may not be on good terms of relationship, but let me protect you and 3.7." Agent 3.2 grabs Agent 3's hands as she wants to keep her comrades safe from the octarians.

Agent 3 gasps as Agent 3.2's hand is as warm as Daigo's, leading Agent 3 to shake and hyperventilate.

"Three?"

"Y- Yeah! Thank you very much!" Agent 3's voice is shaky as if something is chilling on her back.

Agent 3.2 let's go out of worry, realising that something happened to Agent 3 before she met them.

Her usual cheerful persona is slowly going away.

After that, the trio are witnessing those ink cleaners officially called Squee-G, that are known as Suckerfish, cleaning up the mess that happened after Agent 3.4's battle.

"Squee-Gs? They clean up the ink, but they're harmless." Said Agent 3.2.

"Oh my!~ They're so cute!" Agent 3.7 squeals at the sight of an octarian-made machine that is small and less harmful to both inklings and octolings.

Even Agent 3 is surprised to see those little machines that are doing the job by cleaning up the mess they made.

In the end, the place is clean enough to camp in this arena.

"Ngh! Man, I haven't had much sleep since forever!" Agent 3.2 groans as she stretches herself and takes off her uniform top.

Agent 3.7 giggles. "Well, you need some after working a lot."

"Yeah yeah. Yo, three, I'm sure tomorrow will be better for all of us. Today has been a rough start." Agent 3.2 said as she fully cooled down and pulled a little smile.

"Yeah." Agent 3 agreed.

Bzzt!

"Weak"

Bzzt!

"Mmngh!" Agent 3 grunts and shakes her head as the voice in her head is buzzing like this morning.

Finally, they set up the camp and start a relaxing night after their fight against the octarians.

Outside approximately earlier in the afternoon, Callie and Marie, or Agent 1 and 2, dived down to the cave entrance as they distanced themselves from the river.

"I think this is it." Agent 1 puts a Hero Roller on her shoulder while thinking about the place she and her cousin used to go.

"Of course it is. Remember where the zapfish is located? She went inside this hole." Agent 2 confirmed.

"Oh yeah! Hm?" Agent 1 halts, recognising the footprints that are not just 2, but 6 meaning Agent 3 left with the other 2. "Looks like she has company."

"Company? Squit! Agent 1, these are the survivors like Daigo! That means they're doing a suicide job!" Agent 2 exclaims.

"Are you serious!? We have to stop them!" Agent 1 shouted.

"Then hurry up." A voice called from above.

Standing on the entrance and then jumping down in front of the cousins, Agent 3.4 is still taking a zapfish back to Cap'n Cuttlefish while holding out the recorder.

"Ryu! Ahem! I mean, Agent 3.4!" Agent 1 rejoices as there's another survivor. "What happened over there?"

"I found her." Agent 3.4 announced to both Agent 1 and 2.

"You mean Agent 3?" Agent 1 asks.

"Yes. It's Zero."

"You found Zero!?" Agent 2 gasped.

"Yes, but it's not what you expected." Agent 3.4 then tosses the speaker as it reveals both the voices of Rei and Zero as they act like different people.

"Isn't it normal to have two people talking to each other? Or someone talking to themselves." Agent 1 sighs while smirking.

"Hm. Point taken, but what's fishy is that Three woke up talking to herself as if she was role-playing. Some of the actions she made weren't hers, but Zero. The answer is not that simple, Zero's existence is eerily similar to Three's."

"Wait, so Zero doesn't exist?" Agent 2 wanted to know.

"She does. Three will find out the truth behind Zero."

After Agent 3.4's explanation, he holds out his Hero Charger as he, Agent 1 and 2 are encountering a more octarian army outside.

"Go. I'll take care of them. I already splatted these fools. And I'll do it again." Holding a zapfish on his back, Agent 3.4 is ready to go against the horde.

"Agent 3.4. You're a loyal member of the New Squidbeak Splatoon. Thank you." Agent 2 smiles and then nods as well as Agent 1 which leads them to dash inside the tunnel cave entrance.

Finally, Agent 3.4 is glaring straight at an octoling woman while carrying her Octo Slosher.

"A brave young man, you are, but it's a shame that you'll last for a short time. Now hand over the zapfish." The octoling woman called, leading Agent 3.4 to charge his Hero Charger.

"Heh. Over my dead body."

"Then perish into a pool of ink!"

"Bring it on, octo slobs!"

Then begins the battle with Agent 3.4 alone against a horde of octarians led by an octoling.