You were a girl Gryffindor and you were some sort of friend with your Defense Against The Dark Arts, Remus John Lupin (Black because he's married to Sirius), you didn't know that Remus and his husband Sirius Orion Black got a kid your age, 16 years old, his name was Sirian Black.

As Remus asked you to come eat dinner with him and Sirius, he didn't want to say that he got a son, just to surprise you as you accepted the offer and came at Grimmauld place.

You knocked on the door and Remus open the door and hug y ou to welcome you in the house as he told you to come in.

Sirius was in the kitchen as Sirian was shirtless with a necklace and wearing the leather jacket his father Sirius wore when he was in Hogwarts and he stand in the hallway, looking throught drawers, he got Sirius' hair and Remus' eyes.