A/N: So… Yeah. I saw the 3B trailer and HAD TO ignore EVERYTHING else to type this. Because… Seriously!

DISCLAIMER: NOOOOPE, I still own NOTHING. If I did, I'd KNOW what's gonna happen in 3B instead of having to wait…! (groans)

WARNINGS: FEELS… Actually, that's it. Malec will NEVER be something I feel the need to warn about.

Okay… Are you guys ready? I'm not sure I am… But LET'S GO, and see how I chose to use the Malec scenes of the trailer…

Valse Triste

In the aftermath of the chaos Lilith caused Alec and Magnus did their best to recover and adjust. To find a new normal when the warlock no longer had his magic. Magnus worked his hardest to act like he was alright but Alec knew him well enough to see how horribly he struggled. And he did whatever he could to help.

One of their new coping mechanisms was sparring. Whenever Alec could see Magnus's mind wandering to unhealthy places, he took the warlock to one of those intense sessions. Claiming that it was good for them both.

From early on it fascinated Alec to learn something new about his boyfriend. It turned out that Magnus hadn't relied solely on his magic as a self-defense mechanism. That much was proven when Alec found himself pinned to the floor for the fifth time and it became apparent that it wasn't just luck. It excited the Shadowhunter, made his competitive nature tingle.

It would've been perfect. If Alec hadn't realized more and more clearly each day that they displayed more passion while sparring than when they kissed, or in the bedroom. In fact… Once Lilith was defeated the… bedroom activities pretty much stopped. At first Alec imagined that it was because he got injured, then he blamed it on their hectic lives. But as more time passed by he no longer had any idea what was wrong. Why it felt like Magnus was subtly pushing him away.

One day he actually managed to catch Magnus by surprise and had his boyfriend against a wall. They looked at each other, panting hard from more than just physical strain. Unable to resist the temptation, Alec leaned and pressed his lips against Magnus's. Before, the kiss would've lasted for a long time and possibly led to something more. Now Magnus broke it quickly, breathing even harder than before and looking away before remembering to pull the mask of 'everything's okay' back into place. "Excellent move", the warlock complimented breathily.

Alec's eyebrows furrowed while hurt, confusion and dread swirled inside him. He couldn't stay silent any longer. "Magnus… What's going on?" He went on at a look of confusion. "It's… like you're keeping me at arm's length, all the time. You don't even kiss me properly anymore." Those words made him feel like a petulant child. "What's wrong?"

Magnus stared at him with eyes that made the dread grow. And gulped laboriously. "There's… something I need to tell you." He never made it further than that.

Because just then Alec received a message. There was an emergency, such that demanded his immediate attention. He swore under his breath, frustration bubbling hotly inside him. "Looks like we'll have to pick up from here later."

"Go do your job, Shadowhunter." Magnus smiled almost convincingly. Was he relieved or irritated? Both? "We'll talk later."

Things got so hectic that Alec forgot to ask what Magnus tried to tell him. Until it was the end of another chaotic day. Which also turned out to be the day when the whole world began to crumble around him.

In the safety of his office Alec pulled his boyfriend close and to a kiss they both needed. He frowned at the tension he could feel in the body pressed against his. "Are you okay? It's been a long day."

Magnus nodded. "Just… a headache. I'm fi…" He trailed off mid word, color draining from his face.

Cold filled Alec's body. He tightened his hold without even noticing it. "Magnus? What is it?"

That was when he noticed the blood. Appearing dazed, Magnus brought a hand to the skin under his own nose and brushed it gently. A pair of uncomprehending, hazy dark eyes examined the red staining the inquisitive fingers. When the hand slipped the thumb left a smudge to the warlock's jaw. Then those eyes closed and Magnus slumped to Alec's arms.

"Magnus!" Alec cried out. His arms tightened frantically around the suddenly unresponsive man while he lowered them both the floor, gently, gently. Although letting go was the last thing he wanted to do he knew he had to and lay Magnus down with utmost care. His heart pounded incredibly fast when he brushed his boyfriend's cheek in a desperate hope of earning a response. Only Valentine had ever succeeded in bringing such fear in him. "Magnus, can you hear me?"

Nothing happened, until too much happened. At first Magnus was chillingly still. Then began to convulse.

The panic coursing through Alec's veins like fire-hot needless transformed to complete, utter terror. He peered over his shoulder to discover that they'd already started to gain attention. Rage, fueled by helplessness, reared its head when he realized that no one was doing anything to help. "Someone… SOMEONE DO SOMETHING!" he snarled, at the top of his voice. (At the time he was too preoccupied by other thoughts and emotions to wonder why his eyes were blurry.) "Call… Call Catarina! Just… Just DO SOMETHING!" He was screaming it as much at everyone else as at himself.

The love of his life was bleeding and seizing, and all he could do was sit there and watch…!

Alec's head spun while he forced himself to try and focus, to be a cold and clinical Shadowhunter instead of someone terrified of losing their beloved. What did they say during those first aid classes? What was he supposed to do? He was almost certain that unless the patient (Magnus, Magnus, MAGNUS) was at risk of injuring themselves during the convulsions he wasn't supposed to try and stop them. Secure the head… Make sure they're breathing…

Then Magnus's head jerked backwards violently and whatever clarity Alec had succeeded in obtaining vaporized.

No, no, no…! "Don't…!" 'Don't' what? Alec had no idea what he was trying to say. He ran a hand that wasn't exactly steady through Magnus's hair while the still unconscious man's body continued to judder. "Please…!"

The sound of a portal made him tense up and he took an instinctive protective pose above his boyfriend. Braced himself for a threat. Instead he found Catarina. She couldn't quite disguise her shock at the sight of her friend. "What happened?" she demanded while hurrying to them.

Familiar looking blue magic began to glow and Alec knew that he probably should've let go of Magnus. But he couldn't. He shook his head, once, twice. "I don't know." He sounded hoarse from how tight held back tears and emotions had made his throat. He had no idea what was going on and it made things a thousand times worse. "Just… Help him, please…!"

Catarina worked her hardest to do just that. A thin sheen of sweat appeared to her forehead while she concentrated. Magnus continued to twitch, almost like his body was rejecting the magic that wasn't the same which resided in it for hundreds of years.

Then it was over. The magic stopped glowing and flowing. Magnus lay on the floor, eyes closed, still and almost lifeless. Alec stared at the rise and fall of his chest for a full minute, holding his own breath while his mind struggled to understand that the other man was still alive.

He didn't realize that they'd obtained a captive audience until Jace spoke out. "Alec?" His parabatai sounded scared, and not all of it was the archer's terror echoing through their bond. "What's going on?"

Alec shook his head. Again. Looking away from Magnus with immense difficulty, he glanced towards Catarina. "What happened?" He didn't recognize his voice.

Catarina gulped like someone attempting to not throw up. She appeared exhausted and horrified. "I'm… not sure", she admitted quietly, staring at her friend with widened eyes. "I've never felt anything like that before. It was like his very life was being drained from him."

The cold that filled Alec earlier intensified. His hold on Magnus's hand tightened. "But you were able to stop it, right?" Izzy asked when he couldn't find the words.

The expression that appeared to Catarina's face wasn't promising. Nor was the way her shoulders slumped. "I did what I could to shield him against whatever it is draining him, but… I have no idea how long it'll hold against something so strong."

Alec took Magnus to the warlock's apartment because it was the only place that felt safe enough. That day, however, something was missing from the usual sense of security. No matter how tightly he held on to Magnus when he lay beside the unresponsive man, waiting, it felt like his beloved was fading away.

It took several hours before he felt Magnus shiver. A pair of familiar, dark eyes blinked open with visible difficulty, weary and bleary. (How had he missed that constantly growing fatigue before…?)

Alec kissed Magnus's cheek and embraced him just a little tighter. "Hey. How do you feel?"

Magnus swallowed and rubbed his own face tenderly with one hand. The headache was still there, then. "Tired." The warlock looked at him with a frown. "What happened?" The memories seemed to resurface, because there was a shudder. "Oh…"

Alec was so scared that this time he was the one shaking. "Magnus, what… What's going on?"

Magnus stared at the ceiling. Visibly bracing himself. The words that eventually fell were barely audible. "When I traded away my magic… I gave up my immortality as well. And… Now it's apparently starting to catch up with me. Like my father said it would." The final words came out with a bitter edge. "All the centuries I've lived… My body is starting to experience them."

Alec frowned, his chest so tight that he could barely breathe. He couldn't understand because he didn't want to. "What does that mean?"

Magnus gulped. "It means that…" The rest faded away. It took torturously long before those eyes turned to meet his. "Alexander, I'm dying."

Alec couldn't remember what happened next. It was like a large part of his mind shut down. (He recalled vaguely his own voice screaming and shouting. Demanding to know why Magnus would do such a ridiculous, reckless thing and why his boyfriend didn't tell him sooner. Raging how one's own father could do something like that to his own son.) Suddenly he was back at the Institute, doing frantic research. Anxious to find something, anything, that might've been enough to save the man he loved. Desperate to figure out how to undo a deal with a Greater Demon. Over that time several people approached him, asking how Magnus was doing and if he was alright. He ignored every single one of them.

Except for one.

He sensed Magnus long before the warlock spoke. "I thought I should give you some time. But Jace's message was so worried that I decided to come now." Steps approached but stopped a respectful distance away. "Alec… I'm sorry I didn't tell you sooner. But… Whenever I tried, something came up. And with everything that's been going on… The time never felt right."

He did have a point, there – there's never a good time for telling the one who loves you that you're…

Alec turned slowly to face his boyfriend. He wasn't angry anymore. Just scared, achy and so sad that it made him feel infuriatingly close to tears that'd do no good. "You should've told me sooner. I could've helped…"

Magnus shook his head, grief filling his eyes in a response Alec's. "There's nothing you can do. Hasn't been since the deal was sealed. I made my choice, and I don't regret it. Even though I'd lie saying I wouldn't have wanted more time. I know how much Jace means to you."

Those words were like a stab through Alec's heart. He grimaced from agony. "What about you?" he cried out. "Don't you…? Don't you get how much you mean to me? How much I love you?" Why didn't he say that earlier, before it was too late…? "Magnus… I won't lose you. I can't!"

Magnus didn't reply anything. Just closed the distance between them and pulled him to a hug. Alec held back with all his might, for dear life. The tears he still refused to shed burning like wildfire.

They headed back home in a silence that was similar to the one after their awkward first date. Squeezing each other's hands as tightly as they could. (Alec wondered if his fingernails dug into Magnus's skin and felt a sting of guilt.)

Once the door closed Magnus finally spoke. "Alec…" The warlock seemed hesitant, embarrassed to ask for whatever it was that he wanted. "Could you… dance with me?"

Alec blinked twice, slowly. Out of all the things he'd expected to hear, this was among the last. "What?"

There was something incredibly fragile in Magnus's gaze. "I need to not think about… everything. Just for a little while. And… Maybe you need the same." The last time he saw those eyes that vulnerable was when he learned the man's worst memory. "Dance with me."

How was Alec supposed to say 'no' to that? He didn't. At his nod Magnus put on a song the younger man hadn't heard before. Clumsily, not quite sure what to do since he'd never been exactly a dancer, the archer took a hold of his boyfriend. Magnus did the same and they began to move slowly. Soon they were lost in a world of their own.

Until unwanted memories popped up to torture Alec.

/ "Even if I did feel the something for you, would I give up my life for you? You just don't get it. I could lose my family, my career, everything! But at the end of the day… What do you risk?" /

/ "I will use the last drop of my power if it's the death of me." /

/ "Tell me Jace isn't worth it." /

It was all his fault, wasn't it? If he said something… Just one word… If he reminded the warlock that while Jace was important, he couldn't live without Magnus… If he never let go after that kiss…

Unable to bear the memories or the crushing guilt they brought, and determined to attach his mind to something else, Alec spun Magnus. In game immediately, the warlock whirled gracefully before spinning back to be caught by ready arms. Alec wondered why Magnus appeared sad, pained and worried when he dipped the man. Until he felt the tear on his cheek.

The problem with making a deal with the devil is that the devil always wins.

End

A/N: Poor boys! (sniffles) 3B is gonna hurt SO BAD…! (If someone wonders… That line at the end is just me stating a solid fact.) (And, if someone wonders… The title means 'Sad Waltz'.)

SOOOO… How was that? ANY good, at all? PLEASE, do let me hear from you! It ALWAYS makes my day.

Thank you so much for reading! Whoever knows. Maybe I'll see you again one day.

Take care!