(A/N) In this crossover, Hodge, Sebastian, and Max are alive. Everything happens before the seven in Hero of Olympus goes on their quest, but everyone knows each other already.

This is my first fanfiction story I ever written, but do not hold back on reviews, I want to know how bad/good I wrote this crossover

~Disclaimer~ I do not own the mortal instrument, nor do I own the Heroes of Olympus. All the character (besides jack the demigod, not a child of hades, hopefully) is Rick Riordan, and Cassandra Clare characters that I think should meet each other and get confused about life and it meanings. I only own jack and the plot and also Simon and Leo (not really about the Simon and Leo part. but hey, who is not team Leo?)

chapter 1

CLARY POV ~

"Come on Jace, or we will be late." I said playfully. We were walking back to the institute after our picnic in at the park. The lightwoods are cooking dinner tonight for everyone (well not everyone, Simon and Jordan are staying in their apartment).

"Clary we are not going to be late, we have fifth teen minutes." Jace said with that smile that always takes my breath away.

"Yeah, fifth teen minutes then we would really be in trouble." I said lightly, knowing Jace would just laugh. We were walking down a sidewalk when I saw a gold flash from an ally. I stopped walking and partially dragged Jace into the ally with me to see what it was. That was when we saw a kid fighting a…a, well hell I do not know what it was, and the look on Jace face told me that he did not either.

The kid was wearing an orange t-shirt, a jacket that look like it could be a huge blanket compared to his body size, and black pants. He looked pale for some reason. If I did not known better I would of thought he was a shadow hunter, but he do not have marks and he was not using a seraph blade to fight. Instead it was some kind of long gold knife.

The thing that the kid was fighting turned our way, like it could sense us, then started to come for us. Jace, like always, was prepared for a fight. Jace took out one of his seraph blades while the thing jumps in the air to attack us. I was not prepared for this, I always forget that I am a shadow hunter and I need to always be ready for stuff like this.

Jace slash at the demon/thing and it caught on fire, before the blade even touch it, and it turned to dust. "By the angels," Jace said out of breath "what was that thing?" he looked up at the kid who was there staring at us.

"I don't know." The kid said in a rough voice. "Who are you and what are you?" the kids ask, looking at the seraph blade Jace was putting away.

"I'm Clary fray and this is Jace lightwood. We are Nephilim, shadow hunters." I said quietly but loud enough that the kid can hear me. Jace was looking at me from the corner of his eye (I bet wondering why I just told this kid, who is most likely a mundane, that we're shadow hunters).

"I'm jack, I am a demigod." I could barely make out what he said. He looks like he was about to fall over. This kid says he is a demigod, like in those myths. I known better to not think that most myths are true, but to think that mythology gods was real, that just makes me want to laugh! But this is not a time to laugh.

Jace pulled me over to the wall and start whispering. "This kid must have hit his head. Really, to think that demigods are real, just not an everyday normal thing to think." I looked at Jace. I agree but still…

"Yeah, I know, but aren't most myths true? Maybe we should take jack back to the institute and ask Hodge about this." I said quietly. I was surprised when Jace easily nods his head, agreeing with that plan.

"Ok kid; need some help getting up or anything?" Jace asked him.

"Call me jack, no I can stand up myself, and ok I will go to this 'Institute' with you, have not better place to go." He said a little darkly. I frown, this kid must been through a lot, and have good hearing. Jace and I started walking to the institute again, while jack followed. Not knowing what mess we were about to get into.

(A/N) hoped you like this, I will update the next chapter after I get reviews (5? 10? Please?)