Hey hey hey, I know I'm halfway through a longer TID fic right now, but come on - it's Valentine's day, and I couldn't resist. Clace-themed, sorry, hopefully I'll write more about other ships later on. And expect a quick update for part II because I've already written it ;)

What to expect: Clace, slight angst, Sebastian being an asshole, Isabelle being awesome, lots of fluff. Cheesy, soppy, you get the idea. Basically, the equivalent of buying heart-shaped plush toys or those sweets that say stuff like 'UR MINE', idk.

And whether you're hanging out with your S.O or friends, or like me sitting around reading fanfiction (haha funny, right? Sigh...) I hope you have a great Valentine's day!

Accidentally stumbling upon my ex-girlfriend making out with some dude in an alley was not what I expected to do today.

The universe has a cruel sense of humour, I must say.

I was just on the way to meet Isabelle for coffee when I saw them. Isabelle had wanted to meet up because I'd been away for a few months - working part-time jobs and travelling aimlessly. No matter what I told myself, the real reason I'd left was to forget exactly who I was just looking at right now.

Now I was back, back in Brooklyn with worn sneakers and a sense of resignation. Isabelle had immediately ordered me over the phone to meet her at the nearest possible cheap coffee shop. And there I was, taking a short cut through an alley to avoid the busy streets, thinking longingly of coffee, when I saw them.

The guy was tall and strong-looking, ice-blond hair jammed under a contrasting black beanie. He looked strangely familiar, but I couldn't place why. The girl was shorter than him, and she was standing on tiptoes so she could wrap her arms around his neck.

I recognised her paint-splattered jeans and fiery-red curls immediately. It was like a blow to the face - seeing the freckles dusted across her cheeks, her eyelashes fluttered shut, her lips as red as her hair.

Clary.

And as I stared at the two of them - torn between wanting to stalk up and seperate them or to be violently sick - the words pounding in my head were should be me should be me should be me.

Because, just a few months ago, it was me Clary was gripping on to, me she was kissing like she loved me, me that left her lips that red.

And now it was me, standing awkwardly in an alley, momentarily forgetting how to breathe.

"Well, well, well," I said, because I sure as hell wasn't going to just walk on by, "Hasn't anyone told you two about PDA?"

Clary stiffened, and then she had disentangled herself from the guy and backed up against the wall before I could blink.

The guy in question raised his eyebrows at me. His eyes matched his beanie, they were pitch black - and currently simmering with annoyance. "Sorry, do I know you?" he glared.

"Fortunately, no." I said, sticking my hands in my pockets. I didn't look at Clary - I didn't think I could take it.

"Jace," Clary said in a barely-controlled voice, "get out of here."

"I don't see why." I turned to look at her, finally. "It's a public alley. Which brings me back to my point about PDA."

Sebastian looked over at Clary with disgust. "You know him?"

I don't know why this made me so mad, but somehow the idea of Clary never mentioning me - I mean jeez, I think I'm the type of guy that should have a few ballads written in my name - made me see red.

"Oh, Clary didn't tell you?" I said sweetly.

Clary's glare could practically fry me on the spot. I'd forgotten that her eyes were that shade of green - like forests and summer. "Shut up, Jace."

I gave her an incredulous look. "But surely you must have said - "

"Said what?" the guy growled.

I grinned at him. "Said that I was Clary's boyfriend for… oh, a year, maybe? Or was it longer, Clary?"

I was being an idiot, and selfish, and stupid, but I couldn't seem to stop.

"Jace, leave it!" Clary was really mad now. Her cheeks were flushed and her eyes were flashing. "Can't you just stop for once and grow up?"

Ouch. I tried not to flinch as I said cooly, "Where's the fun in that?"

The guy moved suddenly so he was right in front of me. "Don't talk to her like that."

"Or what?" I asked. "You'll beat me up?"

"Sebastian." Clary hissed. So that was the guy's name. It sounded familiar, but I still couldn't think why.

"Don't, Clary." I said smoothly. "If this loser feels threatened, then I don't mind humouring him."

Sebastian shoved me roughly in the chest, but I had braced myself and I barely moved back.

"Sebastian!" Clary said, louder this time, and then she was standing in between us.

"Clarissa, move." Sebastian said darkly.

"No." she glared at him. "Don't touch Jace. He may be an asshole, but he's not worth beating up."

I tried not to show how much that hurt. "Thanks, Clary."

The glare she threw at me was more staggering then Sebastian shoving me. "Shut up, Jace. You know what? I shouldn't have expected anything better from you anyway."

I smiled mockingly at her. "Yeah?"

"Yeah!" she snapped, folding her arms. "Were you jealous? Is that why you're here? Or, let me guess, it's because you can't bear knowing someone - amazingly - doesn't want you anymore? Or maybe, maybe because you want some sort of petty revenge? Any of that hit home?"

I gave up trying to keep my cool. "First of all, Clary," I snapped, "have you ever considered that maybe the universe doesn't revolve around you? Nothing I do is about you, believe it or not!"

"Well, there is one thing that you could do for me," Clary was practically shouting now, "and that's leave me alone!"

Sebastian moved back to her side. "Clary, babe - "

Bleugh, I know. I wanted to vomit.

"Get off me!" Clary pulled her arm out of his grasp. "You know what? Both of you just leave me alone!"

And then she was storming off back down the alley, leaving Sebastian and I staring after her. I was feeling like the worst human being in the world and wishing I could run after Clary, and Sebastian was feeling… confused, it looked like. He probably wasn't used to girls running off on him. I rolled my eyes at the thought.

Sebastian sighed, turned to face me - and punched me right across the face.

This time I wasn't prepared, and I stumbled back into the brick wall ungracefully. His fist rattled round in my skull, and I tasted blood from biting my own tongue.

But I was smiling as I balanced on my feet again. Here, at least, was a distraction.

"Don't go near her again." Sebastian said in a bored tone, rubbing his knuckles. He raised his eyebrows at me as I spat blood onto the floor.

"That's what I was planning to do, believe me." I muttered.

His lip curled as he turned to walk after Clary. "See you round, loser."

Sebastian, of course, didn't think I would throw myself at him. Why would he? He was used to getting his way without a fight.

Unfortunately for Sebastian, I wasn't.

I rammed into him straight on, and we hit the side wall with a dull thud. Sebastian swore, swinging round to push me off him, but I'd already punched him in the jaw.

Sebastian was fast, though, and strong. He kicked out, swiping my legs out from under me and making me crash to the floor.

The pavement vibrated through me. I couldn't draw a breath. A second later, Sebastian was on top of me, fist pulled back for another punch.

I rolled to the side, managing to push him half off me, desperately striking out with fists and feet -

"What the hell is going on?" came a shout.

For a split second I thought it was Clary, but as I looked up from the ground, I recognised the fuming girl as someone else.

Isabelle.

Sebastian got smoothly to his feet, all traces of anger pulled back to somewhere behind his eyes. He smirked, and I was satisfied to see an already-swelling bruise on his jaw. "Hello there."

Isabelle barely glanced at him before stalking over to me. "For goodness sake, Jace, I was supposed to meet you for coffee - not find you mopping up an alley!"

"Who's this?" Sebastian asked me as I got to my feet. "Your girlfriend?"

"If I was I would have just dumped him." Isabelle snapped, still glaring at me.

I would say she's my sister, except she's not technically. We've known each other for years though, and I guess we are related in every way but blood.

"Lay off, Isabelle," I said, trying not to wince, "I was just about to come meet you."

She folded her arms. "Sure you were. You're lucky I was walking by, Jace!"

Sebastian laughed. "Much as I'd love to stay and watch your nanny tell you off, Jace, I'm going to go find my girlfriend. We can finish what we started when I next see you."

As I glared daggers at him, Sebastian punched me roughly in the shoulder with his fist as kind of salute and strutted away after Clary. That asshole.

Isabelle grabbed my arm and dragged me with her in the opposite direction. "You better not expect me to feel sorry for you." she said sternly.

"No, I was an idiot." I agreed, my mind still on Clary… and Sebastian. "Although I do expect coffee. I could really use the caffeine around about now."

I must have looked really pathetic when I sat down in the coffee shop, because Isabelle evidently felt sorry enough for me to buy me a large coffee instead of a regular. "Drink." she ordered.

I gulped it down, my throat burning, and then used up a few napkins wiping a trickle of blood from my mouth.

Real smooth, I know.

"So." Isabelle sighed. "I'm guessing this has something to do with Clary."

I blinked. "How'd you know?"

She gave me a pitying look. "A lot's happened since you've been gone. A lot, i.e Clary and Sebastian becoming a thing."

"You know Sebastian?"

She grimaced. "I'm surprised you don't. He's a real asshole, seeing about five girls at the same time. I saw him just yesterday sidling up to Seelie - you remember her, don't you?"

Now I remembered why Sebastian seemed familiar. I'd seen and heard about him and his reputation before. "Does Clary know?"

Isabelle looked down at her plate. "No. Or at least - she won't admit it to herself. I've tried to talk to her, but she's been keeping her distance since…"

"Me." I said quietly.

Isabelle rolled her eyes. "Very self-centred of you. But yes." She looked back up at me to find me slumped over the table, head gently banging against the wood.

"Oh, stop that." Isabelle said. "You're such a sap."

I didn't even bother with a reply.

"Ugh." Isabelle put a hand on my shoulder to stop me making a dent in the table. "Fine. We'll do something."

"What?" I muttered onto the table.

"Well, Clary needs to know about Sebastian." Isabelle said. "We can't let her go on without the truth. And - " she smugly pulled something out of her handbag, "I have the perfect setting."

I finally sat up and glanced at the something - which turned out to be a poster advertising a band gig. The Mortal Instruments.

"Simon Lewis's band?" I asked in surprise. "Where'd you get that - wait."

Isabelle suddenly looked very shifty - a rare expression for her.

"Isabelle." I said. "You are not going out with that - "

"Simon?" she glared at me. "So what if I am? Anyway, we have time for gossip later. But right now we have to plan."

I sighed, still looking at Isabelle suspiciously. "Well, when's the gig?"

She grinned. "Tonight."

Afterwards, Isabelle walked me back to my flat. I shared it with her brother, Alec, but I hadn't been there for a few months.

I was expecting to find it kind of messy (Alec's not a slob, but he's not that tidy), but my room was as straight and empty as how I'd left it. I'm kind of weird about my room, it's always as neat as a house advertisement - which Isabelle never ceases to make fun of me for.

Alec had left my room exactly how I had, keeping it clean and not dusty. The thought made something in my chest twist as I sank down onto my bed.

Isabelle stayed for a bit - sensing I was lonely and in a bad mood, probably - before leaving with set instructions on when to meet her tonight.

I spent the rest of the day unpacking my stuff and moping around feeling sorry for myself. I had a talent for the latter, I must say.

Finally, I found a vaguely nice white shirt and checked myself in the mirror. I had a bruise under one eye which I couldn't cover up, and my hair was a wild mess from the number of times I'd run my hands through it.

Feeling disheartened, I gave the mirror the finger - which it flipped right back at me - before heading out onto the street.

Isabelle was waiting for me outside Java Jones, tapping her foot impatiently.

"Is that a dress, or a shirt?" I asked her, gesturing to the tight purple fabric she'd managed to squeeze into.

"You're one to talk." she snorted. "You look like someone dragged you backwards through a hedge while you were singing Top 100 Saddest Love Songs."

I glared half-heartedly at her. She smiled sweetly back. "Let's do this, shall we?"

The place was pretty crowded already - but I recognised only about half the faces. Sebastian was there, leaning against a bench, talking to a girl who was not Clary.

"Clary's in the backroom with Simon." Isabelle told me. "So stop twitching round like a depressed meercat."

"Funny." I said.

"Seelie doesn't seem to be here, either." Isabelle noted. "Annoying." She tapped her chin. "If we can't find evidence…"

"Isabelle…"

"Then I guess we'll have to make some." she grinned at me.

I ran my hands through my hair, which did nothing to neaten my appearance. "I really don't think that's a good - "

"Jace." Isabelle stuck her face close to mine. "This is for Clary. We're not doing this to get you back together with her - "

"I know, I know. " I said hurriedly.

"But," Isabelle says, "we both care about her and she deserves to know the truth. Okay?"

I sighed. "Okay."

"Good." Isabelle stepped back. "I need you to go find Clary, and keep her occupied and in the back room. I'll take care of the rest." She looked over in Sebastian's direction with a smirk.

"How long do you need?" I asked nervously.

"Oh," she gave me a wicked smile, "about… 5 minutes. You can do that, right?"

"Five minutes." I muttered. "With a girl who hates me. Sure."

Will update soon! Warning: fluff. :):):):)