Wand and Dagger (HP Fanfiction)

Elizabeth 'Mary' Melainoe is a young witch. She is the caregiver of two young witches and is a newly appointed Professor at Hogwarts: School of Witchcraft and Wizardry. What happens when this Hufflepuff witch becomes co-workers with one of her old friends? (W.I.P) I really dunno what to write here- Severus Snape x OC