A/N- PLEASE READ: This is my first ever fanfic. Just a warning, there are probably a few spoilers for the people who have not finished either of the series. I don't really mind if you write reviews or not, but I welcome any creative criticism or suggestions, as long as they are helpful and not rude. Please try to ignore any grammar, spelling, or punctuation errors, since I do try my best. I hope that you enjoy Immortal!

Disclaimer: I do not own The Mortal Instruments, Percy Jackson and the Olympians, or Heroes of Olympus.

Chapter 1: Some Crazy Stuff Happens

IsabellePOV

"I HATE BOYS!" I scream at the empty forest surrounding me. I can't believe what just happened. Simon, my Simon, ran away from me for no reason whatsoever! Okay, maybe he did have a reason, but still, with all of the "invincible vampire" stuff, he should be able to handle a little kiss!

Fine, I know that I'm overcomplicating this, so let me explain. Magnus, Clary, Alec, and Jace have been plotting all week to get Simon and I together, and Magnus finally created a portal and shoved us through, throwing a picnic basket in after us. I, still being in my gear from hunting a clan of Shax demons with Jace, had been upset about not being able to change into nicer clothes.

After a while of pacing and grumbling, Simon and I finally accepted that we were stuck in the woods that the portal had dumped us in. I was so mad at Magnus though, because I wasn't ready for this, and wasn't sure about my relationship with Simon at that point. Simon looked annoyed too, but he laid the blanket that had been at the top of the basket down in a grassy area. We opened the basket to find bottled water and a peanut butter and jelly sandwich for me, and bottled animal blood for Simon, with him being a vampire and all.

Not in the mood for conversation, I bit into my sandwich. Simon looked at me oddly, then reached out and wiped a streak of peanut butter off of my cheek with his finger, I grabbed his hand and , since he was being adorable, pulled him towards him and kissed him. His arm wrapped around my waist, and I tasted chocolate and blueberry and all of the tastes that were simply Simon. Including the coppery, metallic taste of. . . was that blood? Simon suddenly jumped away, eyes wide, looking horrified. It was then that I felt the sharp pain on my lower lip, where his sharp fang had grazed when it slid out. Simon moved back even more, still staring at me, then abruptly stood up and ran, using his vampire speed to get away as fast as he could.

"Wait!" I had called, wanting to tell him that it was okay, that he shouldn't be afraid of hurting me, since I was a shadowhunter, and he knew I could handle it. But I couldn't tell him, since he was already gone.

"Ugh, why Simon, why did you leave me?" I yell into the woods. I kick over the picnic basket in my frustration, shouting and yelling some more, though I know that it is really sadness that I am feeling right now, not anger. Sadness, because Simon is afraid of his very nature as a vampire, which cannot be changed. I am sad, too, because I am obviously not helping him with his problem, maybe even making it worse.

I am interrupted from my pity party by the sound of somebody clearing their throat behind me. I whirl around, my hand already on the knife at my belt. How on earth did somebody get this close to me without my noticing? And, more importantly, who are they?

"You can put down the big knife, girl," says a teenage goth-looking girl who seems to be around sixteen years old with short, choppy black hair, a silver crown-like circlet on her head, and a mischievous smirk. She is wearing ripped black skinny jeans and a black tee-shirt that has "Not your average badass chick. Better," written on it in yellow with a deflated smiley-face emoji with an arrow through it underneath.

"And why would I do that? It's not like I can trust random strangers I meet in the woods. Especially," I add, seeing that she is carrying a deadly-looking silver recurve bow along with a quiver of arrows over her shoulder, "Armed strangers."

The girl looks surprised. "You mean you can see through the Mist?" she asks. "She told me that you wouldn't be a half-blood," she says more quietly, mostly to herself.

"What mist? Isn't it a glamour?" I ask her. "And who is this she you are talking about, and what is a half-blood?"

"Okay, so I think maybe we should introduce ourselves, 'cause this is going to get a little complicated. I'm Thalia Grace," she tells me, ignoring my last two questions.

"Isabelle Lightwood," I reply. "My friends call me Izzy. Not," I quickly add, "that you can."

"Alright Izzy," she says, earning a scowl from me, "maybe we should walk to my campsite." For some reason, a gut feeling really, I sheath my knife and follow her to a path through the trees. "And," she says, "I should definitely explain who I am. As I said I am Thalia Grace. However, I am also a Hunter of Artemis, the lieutenant, in fact, and a daughter of Zeus. The she that I was talking about earlier was the goddess Artemis, and she knew you would be here and told me to come find you. Anyway, I know this is probably surprising to you, but the Greek gods and goddesses are real."

She glances at me, obviously expecting some reaction, but I simply raise my eyebrows. It's not that I don't believe her, I really do, but I've always figured that if demons could be created by the beliefs of cults and religions, then deities could too, because of the whole "balance of light and dark" thing.

"You're taking this awfully well," she says, looking at me, interested.

"Well, it's not like I don't believe in magic and stuff, and if you are told that all of the myths are true enough times, you start to believe it," I reply, not wanting to give away too much of my shadowhunter origins. "So you're like, the daughter of Zeus and a mund- sorry, mortal, right? And what are these Hunters of Artemis thingies?"

Thalia explains that the Hunters are a group of girls who hunt Ancient Greek monsters with the goddess Artemis, in exchange for immortality unless they die on the battlefield, and they are also expected to swear off boys. When she's finished I say, "So I assume you want me to become a Hunter, right? But what makes you think that I want to be one?"

Thalia says, "You're very perceptive, Izzy. Yes, my Lady asked me to convince you to become one of us, since we are pretty few in number since the Second Titan War and then the war with the giants. As for your other question, I believe you were yelling about some boy earlier, correct?" I glare at her. "And, based on that pissed look you are giving me, I am definitely right."