Severus Snape and the Inimitable Irritation of a Re-Aged Know-it-all (гет)

Severus Snape has lived a life of misery and loneliness since birth. When a precocious eleven year old muggleborn enters his office demanding an aging potion, he thinks she's mad. After much convincing, he goes along with Hermione Granger's plan and finds himself untangling a conspiracy nearly a century in the making.
A witch from the future, trapped in her body from the past.
A former spy turning against his masters.
Another plotbunny that Kpacknoknack didn't have the good sense to leave alone. Updates sporadic probably. Any romance will be when Hermione is reaged to adulthood