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Apologies for all my grammar mistakes.

Spencer Reid POV

"It's a bad one, guys." Garcia hands out the files.

"In the last two weeks, the bodies of four women have turned up on the beach of Santa Cruz. The youngest eight years old and the oldest 32." Hotch tells us.

I look at the photos, none of them look similar so the unsub doesn't have a preference. All the victims have severe burns but the cause of death was clearly stabbing, three stab wounds in a straight line and equal distance from each other, with the centre one going through the heart. I take out a photo of the 3th victim: African-American 24-year-old Jessica Daniels. I look at the photo closely, trying to find anything helpful. Then I see the ring on her finger.

I quickly pull out photos of the other victims. All the victims over 16 have the same ring. A Moon ring. It brings up memories of something I've never told anyone: I am a merman. The Reid's adopted me when I was very little, but I always knew why. The mermaids and men went to war a very long time ago and the mermaids won. All the men were cast out from the sea and forced to live on land.

I've only seen a moon ring once before, when I was a teenager and met a girl at University. She was a mermaid who lived on land.

I stay quiet on the plane ride and on the first day there, not saying anything when we get the puzzling news from Garcia that none of the victims are real. All of them have fake information, only going back a few years.

When we're supposed to go back to the hotel for the night I break off from the others and go for a swim to look for the local pod. I've never been outside the mermen swimming areas (the mermaids run the seas and we're not allowed outside our areas) but apparently the mermaid pods are normally quite small. Only a couple hundred, but according to rumour the pod here is the largest in the world with over five thousand, admittedly not large compared to human population but still big.

It takes over two hours to find them and as soon as I come up to the surface they freak out and try to swim away.

"Wait! I am not here to hurt anyone. I just have a few questions." I yell at the now empty water.

"What do you want to know?" a young voice asks nervously.

I look over at the little mermaid. She's maybe 12 with curly brown hair, bright green eyes, caramel skin and a brave expression.

I send her a kind smile "My names Spencer. I'm investigating the deaths of several women on land and I noticed that a lot of them have moon rings. I was wondering if there's been any disappearances from the pod."

She nods "I'm Emily. Yeah, a few years ago some of the older mermaids got curious about land and decided to try it. They've been going to land school, got jobs. The stories they told were…incredible! So, some of us younger mermaids started a couple months ago, but we all still live in the sea. But over the last two weeks some of them stopped coming back. I heard the Council talking, they're getting worried…. You said they were dead?"

"Yes. I'm sorry" I tell her.

She wipes the tears out of her eyes "So are you a policeman? I heard about them in land school." she asks, mostly likely trying to distract herself from grieving.

"Actually, I'm with the FBI. Do you know what that is?" I ask.

She nods "Yeah my friend Lily from land school's dad is a cop. He was telling us about a specialised FBI team taking over his case today."

I smile at her "That would be my team. We are here to help. Emily, I need to ask a favour of you."

She gives me a curious look "What do you need?"

"Can you talk to the other mermaids who spend time on land? Ask them to be more cautious, stay in groups, tell them what I told you." I tell her not even bothering to ask that they stay with the pod. They would refuse. "And if you can, could you talk to the Council? See if they would be willing to speak to me."

She nods in understanding "My mom is on the Council! I'll go talk to her, just wait here. I'll be right back!" she dives under the water and disappears.

She doesn't come back for over an hour, giving me time to come up with a profile from the new information, but when she does it's with a group of very serious looking mermaids.

"Thank you, Emily, you should go to bed now, it's very late." a mermaid who looks like a older version of Emily says.

"Okay Mom." Emily replies reluctantly before swimming away.

"My daughter told me you said someone has killed members of our pod?" Emily's Mom asks.

I nod and take some (waterproof) photos of the victims out of my bag and hand them to her "The bodies of these woman were found on the beach over the last two weeks." They all look at the photos and I can see from their faces they all recognise them as members of the pod.

"How did they die?" Emily's mother asks.

I hesitate for a moment "They all have burns on their bodies - the ME wasn't able to figure out how they got them, but I believe to be from the merperson ability to heat things up, used on the skin. But they were killed by a three-pronged item through the chest… which I believe to be a trident."

They all glare "You're telling us a merman did this?"

I nod "It fits the profile."

"Profile?"

"The type of person that would have done this. That's what I do I'm a profiler, I analyse the crime scene and all available information to figure out what kind of person committed the crime."

"And what does your Profile say about the killer?" another council member asks.

"White male 20 to 35 years old. Grew up in the foster system and was most likely abused by a foster parent. This makes him angry and he has specifically placed this anger on the mermaids. Blaming your people for banishing him. He most likely spent most of his childhood dreaming of the ocean, believing it would be the place he would find peace. But knows the laws about entering your domain and feels anger at the mermaids for taking what he believes should be his. That anger intensified when he started seeing mermaids on land and he now believes you are claiming what he has and is killing mermaids to make this known. He uses a trident because it was the weapon of choice during the war…."

"Thank you we get the point," Emily's Mom cuts in. "Just find the killer."

They then swim away.

I go back to the hotel and get a few hours' sleep before going to the station. Before we can get started a little girl comes running in and straight over to me "Are you Spencer?"

"Yes."

"He took Emily! She was telling me what you said last night about staying in groups and a van just pulled up and he grabbed her!" She cries.

"It's alright" I tell her trying to calm her down. I notice my team sharing confused looks out of the corner of my eye.

"Do you think you could remember what he looked like?" Hotch asks her kindly.

Crying, she nods and a police officer leads her away. My team immediately turns to me.

"What's going on Reid?" Morgan asks.

We walk into the conference room away from the nosy cops.

I hesitate for a moment, it goes against every law we have to tell humans, but I trust these guys with my life and they need to know. "The victims do have a connection. They were all members of a group, see the ring the ones over 16 are wearing? It's something they get when they finish their schooling."

"So, they're in some kind of cult?" JJ asks.

"Not exactly," I tell them, as I close the blinds in the room and lock the door. "They aren't human. This is the only way I can think of to tell you." I say before summoning some water and wetting my hands. Ten seconds later they're all staring at my blue-silver tail in shock. "All the woman were members of the local pod of mermaids. I believe the Unsub is a merman, angry at seeing mermaids on land."

Morgan is the first to come out of his shock. "Why? Is there some kind of cultural thing about woman not being allowed on land?"

I shake my head "The opposite. We had a war of the genders about a thousand years ago. the mermaids won and the men were banished from the sea. Mermaids and men haven't spoken to each other in all that time."

JJ gives me a confused look "But if your people haven't seen each other in all that time how do you have children?"

"The mermaids can reproduce asexually or with a partner. If the child hatches and it is male they abandon it on the beach," I tell them drying off and standing up. "Most go into the foster system. Some, like me, are adopted."

They all give me strange looks.

"Let's get back on subject" I tell them, taking out my phone and calling Garcia.

"What can I do for you today Boy-Genius."

"Garcia, I need a list of all boys abandoned on beaches in California 20 to 35 years ago." I tell her.

"Okay. Not at all weird… holy cheese balls! 673 baby boys have been left on California beaches in those years."

"How many of them went into the foster system?"

"493."

"How many of them live in Santa Cruz now?"

"24."

"Do any of them have criminal records?"

"Eight of them do. Six are just shoplifting In their teens….. the other two. One of them robbed a liquor store and the other…. Yikes. Tried to kill a girl in his class when he was 17, yelling that she shouldn't be there and that her kind ruined his life."

"What's his name baby girl?" Morgan asks.

"Andrew Johnson."

His picture appears on Morgan's tablet. Johnson is 26, white with blonde hair and crazy blue eyes.

"Guys get this, two weeks ago Johnson lost his job to victim number one, Lis Walker. Guy threw another fit about her kind taking everything from him."

"What's his address, Garcia?" Hotch asks.

"Already sent it to your phones."

I close my phone and head for the door, the team following.

"Agents? We've got the sketch of the Unsub back." A cop hands Hotch the paper.

I lean over his shoulder. It looks just like Johnson. I walk away from the team and over to the little girl. "Hi, we've got a lead on the man who took Emily. I was hoping you could go back to the pod and tell her mother. I promise I'll come as soon as we've checked this out."

She nods and walks quickly out the door.

By the time we get to his house we have a warrant. I turn to the team before we enter the unsubs house. "Be careful. if he wants to kill then it's likely he no longer cares for our laws and will use his powers on you…. So don't get to close 'cause he can boil your blood in seconds."

Rossi and Morgan share a disturbed look. "Any signs to show he's about to do that?"

"Hand movement. If he makes a fist he's boiling something, if he puts a hand straight out he's freezing something, any other movement could be anything from telekinesis to manipulating water, causing a storm or calling lighting. Oh, and if he puts a hand up and twists it around while making a fist, he's about to turn invisible."

"When did we step into a comic book?" Morgan asks.

Before anyone can reply we hear screams coming from the house.

Hotch turns to JJ "How long till the SWAT team gets here?"

JJ checks her phone "Still 20 minutes out."

We hear more screaming.

Hotch looks at all of us "We can't wait. Reid take point on this, if this guy uses his powers I want someone familiar with them in front."

I nod and lead the team into the house and do a sweep, finding nothing on the first floor. We go down to the basement. As we approach, we hear screaming again.

Entering the room, we see Emily hanging from chains with Johnson in front of her, with his left hand extended and making a fist, while burns appear on Emily's arms. A trident is gripped angrily in his right hand.

"FBI! Step away from the girl!" Hotch orders.

Johnson shakes his head, clenching his fists tighter. Emily screams louder. "Her kind ruined my life! They have to pay!"

"This isn't the way Andrew. Look at her, she is an innocent child. She has nothing to do with what happened" I tell him.

"Not yet! But she will. When she grows up, if she has a son she will abandon him on some beach to the fucking humans! The mermaids have to know it's wrong!" he yells.

"I'm not arguing the fact that what the mermaids do with the men is wrong. But this is not the way to stop it." I tell him, trying calm him down.

He unclenches his fist and turns to me. "You know? You're like me? If you're like me then you should understand! Why are you trying to stop me?"

"Because killing people is never the answer. If we want change we have talk to each other." I tell him slowly walking closer.

He scoffs "Talk? Yeah right. You and I both know the mermaids won't listen, they haven't spoken to us since the war! This is the only way." He turns back to Emily with a look saying he's about to kill her.

Already regretting the decision, I extend my hand towards him and close his air way.

He turns back to me uselessly grabbing at his throat trying to get air.

"I'm sorry. But I won't let you hurt her." I tell him, as he collapses.

JJ and Morgan run to his side "What the hell did you do?"

"I temporarily blocked off his air way. He's just unconscious." I tell them, unlocking the chains on Emily with a wave of my hand. "It's alright, you're safe now."

Crying, she clings to me. "I wanna go home."

"It's okay, I'll take you home. But you have to see a doctor first, okay?" I tell her.

She nods and I walk her out of the house as I cuff Johnson and then make a few calls.

"What happens to that guy now?" JJ asks, after Johnson is loaded into an ambulance.

"The same thing that happens to any criminal. He'll be sentenced and sent to jail. We've got people who work in the prisons, making sure that our kind of criminal don't cause too much trouble."

"And the girl? How's her doctor gonna react if he goes to clean her wounds and she grows a tail?" Morgan asks, raising an eyebrow.

"Due to the invention of the internet communication between my kind has become a lot easier. I've already sent a message to the mermen who work in the hospital. They'll take care of everything." I tell them. "I know you all have a lot of questions, but can we hold off until after the case? I've still got to talk to Emily's mother and I'm sure you have lots to do as well."

Hotch nods "When we get back I expect the full story. And I'm sure Garcia will to."

I nod in agreement before heading for the water.

After four hours of being yelled at by Emily's mother and two more finishing up on the case, we fly home. The flight is filled with awkward silence.

Once we touch down we head to Rossi's house and message Garcia to meet us there. When her car pulls up Morgan goes outside to meet her and get her up to date before bringing her into the house. As soon as she walks in, she opens a bottle of water and throws it at me. Seconds later I fall to the carpet and everyone stares at my tail.

"Oh, my god. I thought you were kidding!" Garcia tells Morgan.

Ignoring the conversation, I extent my hand and dry myself. As my legs come back I stand up and walk over to her. "He wasn't. Did you really have to throw water at me?"

She ignores my question "Why didn't you tell us?"

"Telling humans is against the rules."

"Let's go back to the beginning." JJ suggests "You're a merman, mermaids banished the men after a war a thousand years ago, the mermaids abandon all males on beaches? And they all go into the foster system."

I nod "We spend the first 5 years of life in a group home learning the rules before we are sent to ordinary homes… I just got lucky and ended up with the Reid's."

"Do you have your own government? How is everything organised?" Hotch asks, slipping into interrogation mode.

"No, we don't have our own government. We just have people in important jobs who know how to contact each other" I answer. "Look I'm your friend. I didn't want to keep any of this from you but I did, because those are the rules. But you need to promise me you won't tell anyone about this…. Mankind isn't ready for the knowledge of another intelligent lifeforms. I trust all of you but the public isn't ready." I tell them nervously.

They all take a moment to think before agreeing, just as aware as me how mankind would react.

"Wait. Is this the first merperson... people... case we've worked?" JJ asks curious.

"Yeah it is... we have a guy in the mail room who sorts the mail. To make sure no human teams get one of these cases, he usually forwards them to a merman FBI agent, but I guess he missed one."

"Well you can tell him to send the cases to us now. Our job is to help and I personally want to help everyone." Hotch tells me.

I nod, take out my phone and message the appropriate people.

"So" JJ starts curious "If you have all these super powers why have you never used them? Not even a water bottle exploding in Morgan's face after a bad prank."

Morgan laughs "Yeah pretty boy, why no pranks?"

"It's against the rules." I reply instantly. "We are never to use our powers against humans. It doesn't matter if the human is about to kill you. You can't use your powers to hurt them or escape." I explain, the voice of my old foster parent from when I was three hammering in my head.

They all share a look, not seeming very happy with my answer.

I get a response to the text. "They've agreed to let our team work those cases. They're actually quite happy about it, we don't really have that many people in the FBI who can work these kinds of cases."

Before anyone can say anything, I get another message. "And it appears they already need us. A four-year-old was just kidnapped from one of our special foster homes in New Jersey."

Morgan stands up "Not even one night off. I'll call the pilot."

I smile, following the team out. Even when things change they will always have my back and be my family.

This is what happens when you rewatch Mako Mermaids at midnight and start thinking about what Eric said about mermen growing up in foster homes, putting it together with Zac being left on a beach as a baby. And just generally watching too much Criminal Minds.

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