By the time Harry reached the park, he was no longer as sure about his decision to seek out Might-be Snape. He was still physically drained from the nightmare, and his legs felt like it would take very little to stop working altogether. But it was the very dream that had drained him that got him moving again. He didn't care if his legs fell off; he had to prove to himself that it wasn't Snape. Maybe then the nightmares would stop. As if the gods were listening, he found the familiar stranger walking not much further down the path from where Harry entered the park.
Giving up the task of following the man at a distance, Harry forced his legs into a jog. He slowed only a few paces behind the man and matched the obscenely long stride with two of his own steps. His thighs trembled tiredly, but he continued on, thinking what he could say to catch the man's attention. 'Hey, Snape' seemed too brash, but his tired mind seemed unable to come up with much more. Halfway around the concrete track, the point became null. The man stopped walking, and turned abruptly.
Harry froze, but didn't cower as black eyes bored into him angrily. Damn. He hadn't wanted it to be Snape anymore, and, it was. It was definitely the Potions Master of Hogwarts; no one could match that look of dark loathing. Even Voldemort had fallen short, back when he'd been a problem. Harry felt sure that somewhere the gods were laughing at him.
"Stop following me!"
Harry scowled stubbornly. "It's a free park. I can walk the path, same as you, Snape."
"That's Professor to you, Potter." The man snarled almost automatically.
Harry scoffed. "Not out here it isn't. You don't have any power over me here, away from the school." He didn't know why he was baiting the man, but he was. He chalked it up to exhaustion and habit.
Snape glared for a moment, looking as if he were prepared to argue one matter (being followed), or the other (Harry's address), further. Harry straightened and glared back. If the man wanted a fight, he'd get one. Harry was just tired enough not to care at this point. Finally, Snape harrumphed angrily and turned back to the path. When he walked off, he was more stalking than anything.
Harry followed for a bit longer, but soon his legs protested the pace and he was forced to slow, quickly losing sight of the man. The Gryffindor stopped altogether when Snape had walked out of sight, and turned instead towards his home-for-the-summer. He desperately wanted to crawl into a bed for ten or twenty hours of uninterrupted sleep. He returned to the Grangers, where Hermione coaxed him into a day-long movie marathon in front of her parents' telly. Harry found this to be a much better way to spend the day, and when Hermione's parents returned from work, they seemed to agree, joining them in the sitting room. They ordered pizza for dinner and laughed their way through a romantic comedy. That night, Harry thought himself too tired to do much dreaming. His subconscious disagreed, and he dreamt again of a faceless Potions Master in peril, always just out of reach.
-Break-
The next day when Harry spotted Snape, he fell into step behind him again. He didn't know why, but with his dreams becoming more frequent he didn't know what else he could. For no reason he could discern, he became suddenly convinced that this was not Snape, it was someone else. In answer to this sudden certainty, he sped up to walk beside the man and again matched the stride. He glanced out of the corner of his eye, reassured himself that it was indeed Snape, and decided he liked it much better when he could see the man's face. He continued to walk beside the man for close to an hour. When it became clear the man either didn't notice or was ignoring his presence, he broke off and returned to the exercise yard to perform his morning workout. That night he did not dream of Snape.