Stephanie Burgis 
Renegade Magic 

Is Kats untrained magic strong enough to prove she has what it takes to be a true Guardian? Find out in this second book of Stephanie Burgiss Regency-era fantasy trilogy.Nowhere in England is safe from the mischief and magic of Kat Stephenson. With her eldest sister finally married, it seems things are settling down for Kat. But when a scandalous accusation threatens her second sister Angelines prospects, Stepmama swiftly whisks the family away to Bath in an attempt to outrun the gossip and engage Angeline to a respectable suitor. Meanwhile, Kats utter lack of ladylike propriety has prompted the powerful Lord Ravenscroft to expel her from the Order of Guardians before her training has even begun! Anger and exile aside, Kat knows something is not quite right about Lord Ravenscroft. And when her foolish brother Charles unwittingly invokes the furious force of Sulis Minerva at the Kings and Queens Baths, endangering vulnerable cousin Lucy and himself in the process, its up to Kat to rescue her family, find Angeline a proper husband, and prove she has the true dignity of a Guardian.