The Ladies Road Guide to Utter Ruin by Alison Goodman

To most of Regency high society, forty-two-year-old Lady Augusta Colebrook, or Gus, and her twin sister, Julia, are just unmarried ladies of a certain age. But the Colebrook twins are far from useless old maids. They are secretly protecting women and children ignored by society and the law.
When Lord Evan—a charming escaped convict who has won Gus’s heart—needs to hide his sister, Hester, from their vindictive brother, Gus and Julia take Hester and her lover into their home. But Lord Evan’s complicated past puts them all in danger. Gus knows they must clear his name of murder if he is to survive the thieftakers who hunt him. No easy task—the fatal duel was twenty years ago and a key witness is nowhere to be found.
In a deadly cat-and-mouse game, Gus, Julia, and Lord Evan must dodge their pursuers and investigate Lord Evan’s past. They will be thrust into the ugly underworld of Georgian gentlemen’s clubs, spies, and ruthless bounty hunters, not to mention the everyday threat of narrow-minded brothers. Will the truth be found in time, or will dangerous secrets from the past destroy family bonds and rip new love and lives apart?