Harry Potter can't sleep, he has gone without a warm body beside him for far too long, and he therefore decides to act on it in the only appropriate way that Harry Potter would.
After so much travelling, so much exhaustion, he was annoyed with himself that he could not sleep - his bed was warm, and comfortable, and he was wrapped in the sheets as best he could muster - but still sleep eluded him. He felt for the empty space beside him, the space where another body had slept for all of the summer just past, helping him be warm, helping him sleep.
For Harry Potter, life as an Auror was pretty hard - he had been true to his word thus far in helping the Minister for Magic Kingsley Shaklebolt hunt down the remaining Death Eaters since the end of the War, and thus far he and his best friend Ron Weasley had successfully tracked down near on all of those that were left. This very past day, it had been he and Ron who had caught up with a couple who had been hiding down near Kent for several months now, having managed to escape the clutches of every other Auror before them.
A couple of days without much sleep, and Harry had been given a week's pardon to go home and relax, before he was due again to begin a journey to the West where more Death Eaters had been rumoured to flee. And it was during these few days that Harry and Ron had hoped to do nothing else but sleep and eat.
In the bed across from him, Ron had no such troubles sleeping, and was silently snoring with a pair of socks in his mouth that Hermione Granger had given him so he wouldn't snore and wake up the enemy while travelling, and more importantly her when they shared a bed.
But it was another Weasley that Harry lusted over - the small one, with the most fiery and the most silkiest of red hair - Ginny Weasley. She was currently miles away, on the other side of the country pretty much, at Hogwarts with Hermione, both of whom had decided to finish their studies instead of getting into work straight away. Harry admired them for this; he had been pretty sure that it would be quite a while - if in fact ever - before he was able to return to the grounds of Hogwarts, considering everything that happened to him and those he loved there.
But as he struggled out of bed to sit on the end of it and stared out through the window whilst scratching his unshaven face, he sort of wished he was there right now, just so he could see her and touch her and smell her. He reached over for his trunk and rummaged through it as silently as he could, searching deeper and deeper for something... something important. Eventually his fingertips grazed it, and he seized it and pulled it from underneath some old socks.
The Marauders' Map was looking a little worse for wear these days, after surviving so much in Harry's pocket - but its magical properties meant it would never be destined to fall apart, so he was able to tap it with his wand, utter the infamous words, and open it up to find the Gryffindor tower. As always, it was utterly impossible to find one name out of the hundreds of dots that filled such a small place - but after several minutes of staring, searching, he was sure he could see a sequence of letters that spelt out "Weasley".
He stared at it for quite a while, wondering if she was awake too, selfishly hoping that she was; and then he began to convince himself that she was staring out of the window in her dormitory as well, unable to sleep because there was nobody beside her, to keep her warm, to help her relax and get rid of the graphic images from her dreams. But he knew that was silly, they had both had distractions from one another for months now, and although it was quite likely that she missed him, he couldn't see her lose sleep over him.
He folded the map back up and put it aside; glancing over at the clock on his bedside table indicated that it was only just gone midnight, and his stomach wrenched at the thought of staring up at the ceiling for the rest of the night. He stood up instead, pacing the room silently, only Ron's heaving breathing stifled his footsteps, and Harry began to think what he might do, what he must do, to help get to sleep.
In Privet Drive, in the cupboard under the stairs, he used to count sheep - this was a very muggle thing to do, but it often helped him on the dark days, when his Aunt and Uncle and Cousin had been particularly hard on him that day. But that didn't work anymore, and he didn't know why - he had eventually come to the conclusion that the hard days as a unwanted child, living in a cramp space, were nothing compared to what he had faced since then - therefore characterizing sheep counting as child's play.
During his time at Hogwarts, if ever he could not sleep it was usually because of his scar - whilst He Who Could Not Be Named began to rise to power once more, his forehead would burn so badly, that he would eventually pass out from the pain - no counting of sheep was really ever required. It was different now of course - Tom Riddle was gone, the connection had long since dispersed, and though Harry still had that same scar which always pained him, it was now only as pointless as counting sheep was.
But tonight he couldn't sleep because of an entirely different reason - a reason that he was beginning to think could not be correctible so easily.
One more time he looked across at the bed that Ron occupied, his mind racing - by now he had pretty much made up his mind that he had to do it, he had no other choice. He turned away from Ron and began to rummage through his trunk once more - he pulled out some clean jeans, a clean shirt, an old school jumper, his travelling cloak and his shoes - followed by something silky, long and thin and imperceptible.
He hastily got dressed, took his wand from the bedside time, as well as the map that he had placed there earlier and crossed the room to the door. He put his hand on the door knob and carefully turned it, making sure to look down at Ron in case he woke up and started asking questions on where he was going. But Ron merely snorted a little, turned onto his side and continued to sleep whilst Harry quickly snuck out into the cool night air.
Casting a glance of his surroundings, he saw nothing but tall broad trees in every direction - Remus Lupin's lodge was known about by very few, and its location known by even less - it therefore acted as Harry and Ron's safe house from those that might still have the strength to make an attempt on their life. Not that there was much threat - but better safe than sorry, that was the Minister of Magic's mentality - he did not take threats on his employees lightly, whether they be Harry Potter or not.
Harry turned on the spot and disappeared.