AN: again, an idea that wouldn't leave me alone. Posted on Tumblr originally. Hope you enjoy!

Pillow slips. Who'd have thought something so small could lead to such a huge accidental epiphany?

His mind wandered as he stared at the blank sheet of lined paper in front of him; it was cast back to the equally white pillows he lay his head on every night. But when he'd woken up in the morning, they weren't so white anymore: he noticed red spots on them, and figured he must have been choking in his sleep. His chest felt as if it were rattling with every breath; it felt tight, on top of that, when he realised:

Dean will see this. Dean will ask questions.

That was when he realised that he couldn't hide this forever. Sure, this time around, he could offer to selflessly do all the laundry, so as to craftily avoid Dean seeing the pillow slips, but eventually he'd come undone. Whether it was sooner or later, there was a good chance – even after his little pep-talk about wanting to make it out of these trials alive – that he was going to keel over once they were done. Not before they were done (they were getting done, he owed Dean that, at least) but maybe afterwards. And that would be something he couldn't hide.

But he could at least make provisions for it. He wouldn't leave Dean with nothing but an 'I'm sorry' and a last breath. He didn't even want to leave him a short note, because every time he considered it, 'missed you, love you!' and the scent of freshly-baked cookies sprang to his mind from a terrible, sad place in his past. He wanted to explain himself properly; to help Dean understand why he needed to hide this from him until the trials were done.

He snapped back to the present when he realised he'd already put his pen to the paper; had already scrawled, Dean. First of all, I'm sorry. I honestly wanted to come out of this alive. But we both know better than anyone that you can't always get what you want.

He blinked, startled for a moment. But he shook it off, and continued writing. That part could stay at least.

I'm writing this in late February. I'm sick and I know that I'll either complete these trials and live, or complete them and die – that's why I'm writing you right now. I need to explain that I wasn't lying to you by hiding this. It's just that, if you knew, you'd call the whole thing off – the trials, the responsibility of me saving your ass for a change. And honestly, Dean, I don't want you to suffer through this.

He paused for a moment, wondering if what he'd written was too chick-flick for his brother's taste. He decided it was just the truth, in the end. Last time . . . Back at Stull, he hadn't got to say much more than a few words, and he hadn't felt they'd been enough to express everything he wanted to say to Dean. Sorry, thank you, and goodbye. All he'd managed was –

'It's gonna be okay, Dean.'

He continued his letter: I guess we're about even now – I mean, I broke the world once, and I jumped into the pit to solve it. But even then when I came back, I was this

He struggled to find words more eloquent than 'soulless dickbag' for his final letter to his brother. He smirked despite his grim task, and mediated his language. What if Dean had kids he wanted to show this to? He couldn't use language like that. He wouldn't want them to think badly about their uncle Sammy, as he'd inevitably be known. He didn't mind, though.

horrible person. Then I was a mess of hallucinations and buckets of crazy . . . It all just didn't seem fair on you. So, that's why I'm hiding this illness. I don't want to burden you like I did before. I'm dealing, this time – I really am. I promise. I'm making it up to you. I figured I'd about made up for my mistakes already, but maybe this extra sacrifice will just make sure I leave for good with an overall positive set of memories to leave behind. Good to cancel out the bad.

He sighed as he broached the topic of 'leaving for good', scrubbing at his face with his left hand, and squeezing his eyes shut to combat the dull thud of a headache he was beginning to develop. Maybe it was to do with the trials – or, maybe, it was just the pent-up emotion trying to burst out of its brain right through his skull. Urgh.

That's one more thing I want to talk to you about. Don't – as in, DO NOT – try and bring me back. I don't mind if you bury me, salt and burn me, whatever. Just make sure you don't do anything stupid, Dean. And bury me with Mom and Dad. I don't care if you think it's cursed ground, I think it's fitting. If you have my body, it should be with them. I know it's a pain in the ass to drive from Lebanon to Greenville, but I've buried you in Illinois before now, so fair's fair.

How could he make Dean see that this wasn't sad . . . Well, it was kind of sad – if Dean ever read this letter, it would be because he was dead – but it didn't feel like a suicide note, or in any way mournful. He just wanted Dean to see. He wanted to say –

I've made this decision, Dean. Don't blame yourself for what happened to me. As hunters go, I'd like to think I did more good than bad. I've reached thirty, too, which is a pretty big goal for one of us. While I didn't always enjoy hunting, it was always tolerable. After all, I got to see things that no one else would ever get to – that no one else would even believe existed. And I've killed them all. So I don't mind that this is what killed me, not a heart attack or any other kind of 'normal person' death, because

Sam jumped as a tear rolled off his face and hit the paper with a dramatic splash. He had surprised himself: when did he start crying?

He wondered if the next part was implicit in his words, or if he needed to write it down verbatim. His brother wasn't the best at subtext sometimes, and he imagined that he'd want these words written down for the whole world to see, if this were Dean's letter to him:

at least I got to spend this time with you. You're the best brother anyone could hope for. Even with your God-awful singing and your stupid pranks.

Don't come and visit me too often. I want you to have a career, now all the demons are (hopefully) locked away in Hell, not mope about some graveyard in east-Jesus nowhere.

I'm glad you'll get to read this, even though I'm not sure exactly what it is – whether it's a letter, or a will, or whatever. This is a pretty crappy will seeing as I don't really have anything to give to you: it's all yours, too, really. Just look after my books, and – of course, I don't need to say it, but take care of the Impala, too. Thank you, Dean.

Your brother,

Sammy

Sam sniffed, and coughed a little embarrassedly, trying to erase any evidence of his tears from his face. But when his coughing sprayed tiny droplets of blood onto his hand, he froze. Had any got onto the letter?

He frantically searched the lined paper, looking for any trace of his suffering. This was not what he wanted. He didn't need Dean seeing the little red splotches and overwriting everything he'd just written with pain and self-hatred, after seeing the evidence of his malaise at the hands of the trials.

His heart rate slowed gradually as he found that he'd managed to keep the paper blood-free. Smiling in relief, he folded it up, and sealed it in an envelope, taping it up so it couldn't be tampered with. This was how he wanted Dean to think of him, if it came to a dramatic Death By Trials: happy, and thankful for his life, rather than hurting and alone.

He couldn't tell Dean about the letter, although it hurt that he might not find it. He would tuck it behind Dean's photograph of Mom later, when he could sneak into his room. He knew that, after his death, Dean would probably move away and that involved packing up his things, including the picture. If he survived and they never moved, however, Dean wouldn't displace the photograph, and he wouldn't find the letter. Sam could remove it if necessary.

But, as another hacking coughing fit plagued him while he stuffed the letter into his back pocket for the time being, he thought bleakly that there was little chance of that second eventuality.

At least Dean would understand now.

p.s. Any ideas for oneshots you'd like me to write? Let me know!