Orphaned by the murder of his father, rejected by his grandfather, and consigned to the harsh life of an orphanage, Percy St.-John’s existence is marked by hardship. Under the cruel oversight of Reverend Mortimer Lovecraft, Percy endures a world filled with pain. When fate finally allows him to escape, Percy faces new challenges on the streets of London, where survival means scrounging for scraps and facing dangers at every corner.

Hope appears when he finds shelter in the locksmith shop of Tobias Finermann and his kind granddaughter, Hannah. Under their care, Percy begins to rebuild his life. With the help of a mysterious Guardian Angel, he discovers a newfound fascination for locks and safes, unlocking skills that will change his future.

But secrets linger in the shadows. As Percy settles into his new life, he and Hannah suspect that old Mr. Finermann is hiding something. Strange visitors and late-night outings hint at dark dealings that could place them all in danger. As Percy navigates these mysteries, he discovers that he might have a greater purpose than he ever imagined—a journey that will lead him to become The Midnight Boy.