The Counterfeit Heiress

Warning - Spoiler in the link

A few years ago, every mystery I read seemed to have a subplot (usually one that detracted from the main story and/or involved "old friends" never mentioned before or since).  My current trend is parallel stories, and my authors use it much more successfully.  The Counterfeit Heiress is the third consecutive Lady Emily book to include a separate narrative which adds a new perspective to the main mystery.  It's no surprise that Tasha Alexander does this well; And Only To Deceive used this method to give Lady Emily a reason to solve her husband's death.

Alexander's secondary storyline features Estella Lamar.  One of Cecile's old friends, the mysterious world traveler has only been seen in blurry photographs since abruptly leaving on her travels.  Years later, someone claiming to be Estella shows up at the party of the season, a costume ball at Devonshire house thrown in honor of Queen Victoria's Diamond Jubilee.  Cecile recognizes her as an imposter and the woman, wearing a costume very similar to Emily's, runs off.  Someone murders the imposter before anyone can identify her and Emily and her husband Colin make discreet inquiries at the request of the Duke and Duchess of Devonshire.

Cecile, meanwhile, begins to wonder what happened to her friend Estella?  She's been sending dispatches back from her travels, but no one has actually seen her.  Upon analysis, her travels seem impossible, taking too little or too much time to get from point to point.  Estella's Paris and London homes are both fully staffed despite the fact that the mistress of the house hasn't been in residence for over 20 years.  Has she been kidnapped?  Is she even still alive?  Inspired by a true story, Estella's fate caused her imposter's death, but Alexander still manages to make the murderer a mostly sympathetic character.  It's a nice twist on the traditional mystery.