A/N: Part five. Posting this one early so I can get the whole thing out before the long weekend is over :-)
November 20th, 2003, Yet another evening without the insufferable witch
Miss Granger,
This has been quite enough. If you continue to–
An insistent knock sounded at the door, interrupting his writing of a carefully planned tirade. With a dark scowl, Snape laid his quill down with more force than was strictly necessary and pushed away from his desk, striding across the room and yanking open the door.
A scathing remark died on his lips as the door swung open to reveal not a terminally lazy student begging for an improved grade, but a shimmering silver otter cavorting gleefully in an empty corridor.
Suddenly faced with an uncomfortable sense of déjà vu harkening back to the days of the elder Weasley twins and their antics, Snape moved his hand to wrap securely about his wand before stepping out into the hallway. When the expected assault never materialized, he relaxed only slightly, still all too suspicious of the inexplicable patronus currently gamboling about him in ever-tightening circles.
The damn thing wouldn't slow long enough for him to get a good look, but if he hadn't known better he would have sworn the charm was his own. Distracted by this thought, he let the otter slip momentarily from his gaze, only to be surprised when the animal bumped insistently against his back.
He spun, brandishing his wand threateningly at the mischievous creature, but the apparition simply darted down the corridor and eagerly back, like a dog beckoning its master to follow. He raised his brow as the otter paused for a moment, as if it were waiting for something, only to repeat its earlier actions when he didn't move. The small silvery animal repeated this ritual several times, each time going a little bit further down the hall.
Snape knew he was intended to follow the patronus wherever its caster had intended, but he was less than inclined to follow a spell whose source could be anywhere or anyone. It wasn't until the otter again spun to a stop in front of him and bared sharp little teeth with a fearsome growl that it received any sort of reaction from the assistant headmaster, a bark of surprised laughter.
The creature cocked its head at the noise and again took off down the hallway, this time not pausing to return, as if it were certain the man would be following this time. And follow he did, his curiosity at the persistent temerity of the conjuration overwhelming his inherent need for caution.
The otter bounded through the maze of castle corridors, the man following at a rapid pace, until it skidded to a stop in front of an unassuming wooden door tucked away at the end of a musty, little-used corridor. With one last expectant look in his direction, his patronus guide vanished into air.
When a barrage of spells showed the door to be nothing but a door, he placed his hand on the knob, hesitated just a moment, and pushed it open. Warm brown eyes met his.
"Hello, Severus," his insufferable witch murmured.