Siriusly, Severus? A time potion?

In the Spring of 1976, Severus Snape is determined to get Lily Evans to accept his apology. What better way than a time travel spell? He can just skip the entire summer and come back to school with all of the sincerity but none of the aching loneliness that will come from a holiday break at Spinners End without Lily.
The Marauders use their map to keep Snivellus from ever coming near Lily Evans again. When they see him acting shady in the potions lab, they know what they need to do.
A duel of misfired dark magic and the five young wizards head to the hospital wing, only to realize that the entire school has changed. Apprentice Pomfrey isn’t the hot healer Sirius would flirt with, she’s a Madam now and looks to be old enough to be their mother.
That’s not the only thing that’s different, laying in one of the beds is a student who looks just like James, and a severely injured young witch who won’t stop screaming.