Kat Stephenson is precocious and, yes, incorrigible. Her 'desperate to climb the social ladder' stepmother is often at her wit's end, but she is her mother's daughter, the mother who worked magic as a Guardian but was expelled from a mysterious Order. After somehow finding her way into a grand hall, some older Order members find Kat's ready to turn everything inside out. What they also don't expect is Kat's determination to do whatever it takes magic-wise to help her siblings Elissa, Angeline, and Charles, even if it includes becoming a highwayman.This book was all kinds of magical and fantastical. Kat is perfect, not uncaring but strong, both in will and in spirit. Very clearly a girl who grew up with her older sisters telling her their memories of their mother instead of having memories of her own. Elissa is practical, Angeline is working magic on her own, and Charles... well, we don't see a lot of Charles, but we do find out he's hopeless.The little twists and turns and surprises and magic bits were tons of fun. Nothing really seems to go right for Kat. Her stepmother's close to heartless, her father rarely stands up to her stepmother (they're his kids, not hers, after all), Elissa won't listen to reason and follow her heart, Angeline won't listen to Kat and share their mother's magic books, and Mr. Gregson and Lady Fotherington won't listen like only adults can and try to bend Kat to their will. Life really sucks for Kat. It isn't until everything comes out in the open, everything and anything and all the secrets people wanted to stay secret, that Kat finally has the ability to make everything work.If I was younger and read this book, I would've loved it even more. I love the Regency England setting, I adore that time period, and I love that Stephanie Burgis has created a world that is so believable even with the weaving in of magic. It just makes Kat's England more sparkly, more unpredictable and fun.I'm not sure if this book would be classified as middle grade or YA. It reads like a YA novel, seems to be about as long, but Kat is twelve years old. Maybe older middle grade/younger young adult.Kat is full of incorrigible charm, making her an ideal narrator. Readers will enjoy her unique take on her surroundings, will admire her desire to rescue her siblings while being the youngest, and will cheer when she, against all odds, saves the day.