Madeline Black lost her parents at a very young age. Her mother was murdered by 'He-Who-Shall-Not-Be-Named', while her father got sent to Azkaban. Her mother came from a muggle family, and so she grew up with her muggle aunt. Until the year she turned eleven and learned she was a witch.
The Summer before Madeline's third year, the Daily Prophet headlines that the notorious killer Sirius Black has escaped Azkaban. Questions start to pop up in Madeline's head while strange things start happening during the school year. She finds out the truth about her family, finds herself in danger, and catches herself to have caught feelings for one of her best friends.
Disclaimer: I don't own Harry Potter, all rights go to J.K Rowling. I only own Madeline, her storyline and any other characters that are not mentioned in the movies or books. I, however, do not support J.K Rowling or her views.