Hermione and Ginny Come Home

Hermione and Ginny went back to Hogwarts for eighth year while Harry and Ron did not. 21 years later, Hermione and Ginny have disappeared off the face of the earth, only to return to the 21st anniversary of the Battle of Hogwarts. And not alone, they have mysterious husbands and 8 kids in total.

Disclaimer: I own nothing but the plot. J.K. Rowling owns the rest.