The Twin Who Lived: Secrets of the Serpent

After rescuing a woman named Nagini, inventing two revolutionary Auror devices, and discovering a Witcher ancestor from another world, Sapphira Silverthorne returns to Hogwarts for her second year. But Sapphira knows something no one else does: the Chamber of Secrets will open. Determined to find Tom Riddle's diary, stop the attacks before they spiral out of control, and prove Hagrid's innocence, Sapphira throws herself into another year of mysteries and challenges. Between trying out for Slytherin's Seeker position, managing her growing reputation, and enduring Professor Gildroy Lockhart's lessons, she quickly learns that changing the future is easier said than done. The Chamber is waiting. The serpent is stirring. And the secrets of Hogwarts are far from buried. — Description from novelcodex.org