Lumos

"Who is she Albus? She looks so familiar." Severus pleaded with him, thinking of the auburn haired girl that had sat in the Great Hall earlier that evening.

"She is your daughter Severus," Dumbledore told him, as his knees went weak.

"Wha- that's not possible." He croaked, sitting down very quickly. Dumbledore peered at him shrewdly over the top of his glasses.

"I'm sure you'll find that she is very much your and Lily Evan's daughter."

When Katherine MacDonald shows up at Hogwarts, Severus is shocked to find that a Christmas Eve long ago resulted in him having a daughter-and Lily had never told him about her. After eleven years of her godmother refusing to tell her who her parents are, Katherine is desperate for answers about a family she never go to know. Only is it at Hogwarts that she slowly starts to find out who they are, and who she gets to meet.
Katherine learns many things throughout her time at Hogwarts, including how to love, how to forgive, and most importantly, that family isn't always blood.