Sasha; The Widows|HPxAvengers

"I am strong because I've been weak."

"I am fearless because I've been afraid."

"I am wise because I've been foolish."

What would of happened if the Marauders had a fifth person in there group? No less then a girl.

Sasha is different from her twin sister Natasha, yes both of them are trained assassins, known to the human(muggle) world as The Widows or The Black and Red Widow. But the difference between the two is that Sasha attended a school for witches and wizards, Hogwarts.
Sasha attended it for all the seven years until something was revealed a month before the NEWTs were supposed to take place.
She immediatly left her only escape of the toture she goes through at 'home', but she went there anyways, for that is the only place she knows of.

Years later in 2005, a group of people fell through a hole and landed on the school Sasha swore never to set a foot on again.

In which the group of people, the whole school and some other people watch the life of the Avengers

Or

In which HARRY POTTER and his friends finally gets the answer about the mysterious women that is in the photos, they have asked about.