John couldn't sleep. It wasn't the same nightmares that he had been having ever since he moved in with Sherlock, ones with blood and gunfire and sun and sand and things flying overhead. No, this was new. What exactly, Sherlock wasn't sure, but he intended to find out.
John didn't know he was having them. He never woke up in the middle of the night sweating and panting like he had just finished a marathon. Not from those dreams. The other ones, with the sun and blood and soldiers, he woke up from those, feeling as if he was still there. Sherlock could tell. John was different in the morning after he had one of those. He smelled like fear and shame.
Sherlock could tell when John had the new nightmare, because the writhing around in the bedroom above him would wake him if he was sleeping, but after those, John wasn't different. Just tired. Worn out. Exhausted before he even began his day.
Sherlock suspected what they were, but if John didn't even recall having them, Sherlock didn't want to force the subject.
Until one day John fell asleep while they were supposed to be waiting for a suspect.
They were at their favourite Chinese restaurant, and Sherlock was so intensely focused on watching the park across the street that he didn't notice john was nodding off until he turned to get a drink and saw him face down in his noodles.
Sherlock poked him with a chopstick and was amused to find that when John sat up muttering things to himself that he still had a noodle stuck to his face. Sherlock kindly removed it for him with a chopstick. John was not amused.
After John returned from the loo, claiming to be 'freshening up', Sherlock thought this would be a good time to bring up John's lack of sleep.
"So, not sleeping well."
John knew this was a statement, not a question.
"Now would be a good time to discuss it." He leaned forward.
John eyed him uneasily.
"What about the case?"
"Unimportant." Truth be told, Sherlock had already figured out who did it and texted Lestrade while John was in the bathroom trying to get noodle grease out of his hair. Unsuccessfully, Sherlock noted. But there was no need to inform John about this triviality.
Sherlock waited a beat for John to say something. He didn't. Sherlock sighed, "John do I really need to go through all the deductions? I know you've been having more nightmares that you don't remember, and that's why you're so tired." He paused, glancing at John. "So. What's the issue?"
John was eyeing Sherlock suspiciously.
"Why does it matter to you?"
"Because your lack of sleep is interfering with my work," he huffed. John only raised an eyebrow. Sherlock continued reluctantly. "And because you're my friend."
"And I worry about you, okay?" he snapped. "Now just tell me what they're about!"
"Well you said yourself that I don't bloody well know!"
They stared at each other for a moment before Sherlock looked away.
"It has to do with the river," Sherlock said softly.
Three weeks ago on a case, Sherlock had been thrown into the Thames unconscious by a gang of thugs as a method of disposal. Thankfully, John had been following them, and was on the shore nearby when it happened. He called Lestrade and dove in after Sherlock. But it was cold and Sherlock was heavier than John expected in his water logged coat, and for a little bit it seemed like neither of them would make it back to shore. That was when Lestrade and all his men showed up (a little too quickly if you asked John, he suspected Mycroft had a hand in that) and pulled both of them out of the water, Sherlock unconscious and unbreathing, but still alive.
Two days in the hospital and Sherlock was fine, but John was obviously more shaken up than he let on, because it was not too long after that the new nightmares began.
A pained look crossed John's face, and Sherlock knew that he was remembering the dreams.
He visibly slumped, and Sherlock could tell he didn't want to share. But he also knew it would be important for John to overcome this.
So he waited patiently for John to speak, not pressuring him.
"It was just like it actually happened. You were thrown in the water and I jumped in after you." Sherlock nodded. He obviously didn't remember this part, but had been told it many times. "Except this time Lestrade isn't there. No one is there. And I know no one is coming. It's just me and you in the water. Alone in the water. And I know that I have to keep swimming or I will lose you. I will lose us."
Sherlock nodded, and took John's hand reassuringly.
"Completely logical. That's why you wake up exhausted in the morning. You've been swimming all night. But there's really no need for that. I'm fine; see?"
Sherlock motioned to himself and John cracked half a smile.
"Now let's get the fortune cookies and go before you fall asleep in the noodles again. Very bad for the complexion. Besides, I have a feeling the fortunes will be excellent tonight."
John snorted, but concurred.
And sure enough, John's fortune cookie read 'you are stronger than you think yourself to be' and Sherlock's read 'your friend cares deeply for you, trust them with your life'.
John shrugged it off, and Sherlock really didn't care, although found it amusing.
John never had those nightmares again. He had the ones with the bullets and dying soldiers bleeding in the sun, but never the ones where they were alone in the water.
And that, Sherlock thought, was progress.