They'd finished their cups of Earl Grey, hot, and the boy had gone to get ready. The older man watched him, smirking and shaking his head slightly in amusement.
The meticulosity with which the boy was arranging the sleeves of his robe would not have looked out of place in the older man's mirror. On Harry, it simply looked... odd. There was no other word for it. He watched until the boy - the man - looked up, caught him at it, and gave a wry smile accompanied by a self-conscious shrug.
"Are you ready, Professor Potter?"
"We'll soon find out, Professor Snape."
Snape nodded. "After you, then," he said, lifting his chin toward the door of their quarters.
Harry headed toward the door, then turned and faced his former Potions Professor, now his colleague. "Dad..."
Snape held up a hand to stop him. "You'll be fine. You've already taught defense, remember. You can do this." His black eyes softened into something startling, given it was... well... him. A warm, reassuring smile lit his face and took up residence.
"You'll be fine, son," he said, and turned them, once again, toward the door, toward the Great Hall, toward the Sorting Ceremony, and the young witches and wizards of Hogwarts.