He repeats this cycle for what seems like hours--he doesn't keep track of the time as it would be distracting. A close observer might notice that, while he concentrates, his black eyes flicker in and out of focus. When he rests, his breathing is ragged, and his pulse quickens. It is as though he rests from practicing for a marathon rather than the impending arrival of one Miss Luna Lovegood.
He finally sighs, stands, and prepares to leave his office for dinner in the Great Hall. He hopes that none of the remaining staff are there, especially as he will arrive later than the usual meal time. After the strain of his practice sessions, he finds he rarely has the energy to engage in mindless prattle with his colleagues.
With a flick of his wand and the characteristic swish of his robes, he goes. The wards recede, then regenerate as he exits through his door. The portraits in his dungeon hallway mutter to each other as he passes. They have noticed his recent change of mood, although he makes it a point to ignore them as much as possible.
The Great Hall has only one round table during the summer, rather than the usual four house tables. Severus is pleased to find only Minerva left this evening. Although he enjoyed the company of and respected her predecessor, Albus Dumbledore, Headmistress McGonagall is satisfactory in ways different than the befuddling old man. Severus appreciates her straightforward manner, her businesslike management style, and particularly her tact--she is far more inclined to stay out of his affairs than Albus, whose good nature often came with the unfortunate side effect of good-natured meddling.
"Good evening, Minerva." He chooses a seat near her and pours a glass of wine for himself as dishes begin to appear before him. "Is that the latest Transfiguring Monthly?"
She raises an eyebrow at him from behind her journal. "How coy, Severus. I quite enjoyed your article this month. Although, I must question your authority on transfiguration of medicinal potions. I don't think I've ever heard of you putting forth such effort in fields outside your own."
He swallows a sip of wine and smirks at her. "On the contrary, Minerva, I quite enjoy subjugating the lesser magics in pursuit of better potions." He stifles a chuckle as he sees her dark expression in the corner of his eye, and decides to change the subject. "Speaking of lesser magics, do you know when Miss Lovegood will arrive?"
Minerva glances at hearing his nonchalant tone, but doesn't raise her head from the journal as she answers. "She will be coming on the train, I believe. Why do you ask?"
"As she is one of the infamous Potter clan, I would like to enjoy my last few precious days of peace as much as possible." He refills his glass as he replies. It is more than he usually has at dinner, but he wants to sleep soon after the meal. He is still weary from his practice session.
Minerva chuckles and finally looks up at him. "I believe you'll find that Miss Lovegood has grown up a bit since you last met here. Personally, though," she says as she dives back into the journal, "I think you might dread her for other reasons this time 'round."
Severus looks at her for a moment, gauging how much she might know. She has returned to her reading, or has at least pretended to, so he stands to leave. "I doubt that very much. Have a good evening, Minerva."
Whether he doubts if Miss Lovegood has changed or whether he doubts that his reasons for dread have changed in the past seven years, he does not clarify. Minerva watches him leave, a half-finished glass of wine the only trace of his presence left on the table.