Mary Marsh, overcoming her own heartbreaking past, is hired by Christine Longfellow, the daughter of the Countess of Renn, to put together her wedding trousseau.  Christine's strange behavior worries Mary, but she passes it off as pre-wedding jitters.  When an accident claims Christine's life, everyone is stunned.  It doesn't take long for her older brother, Marcus Longfellow, to return home from Egypt to investigate his sister's death.

The Earl of Renn is a powerfully attractive man.  After hearing Christine's descriptions of him, Mary was still unprepared for the physical attraction she felt for Marcus.  However, even though he's asked her to stay on and help him find out the answers to Christine's death, Mary realizes that nothing can and should come of their feelings.  She is a commoner, and he is the Earl of Renn.

However, during the course of their investigation, Mary can't control her feelings for Marcus any more than he can control his for her.  Pushing aside her own past, she decided that this might be the last chance she has.  She knows that their romance can't go anywhere, but she gives him her heart anyway and resigning herself to be happy with what little she had of him

Marcus can't deny his feelings for the lovely seamstress.  He is shocked, though, to discover exactly what she had been creating for his sister.  Lingerie, shocking and revealing, has teased his senses until he's nearly overrun with desire for this beautiful spinster.  Coming back to England wasn't his wish, but his sister's.  Before her death, she had expressed an unease, a fear that she wouldn't name or define.  He'd left Egypt, where he'd been working with the hieroglyphs, to come to his sister's aid, albeit too late.  Now, as the answers become clearer, Marcus faces the realization that he needs Mary in the most simple, yet complete way.  However, learning about his sister's death leads him to a rather shocking revelation about his own family.

WHEN IT'S PERFECT is a perfect example of Ms. Ashworth's talent.  We first met Mary in SOMEONE IRRESISTIBLE when she stole Nathan Price's priceless jawbone, discrediting him in his profession.  Experiencing tremendous guilt, Mary feels like she can't be forgiven for nearly ruining a man's life.  Sewing her lingerie for the wealthy brides has given her something that she can do on her own and be proud of herself doing it.  Mary is a character with which everyone can identify because we've all made mistakes.  She's courageous, entering a relationship, knowing the outcome will break her heart, just to experience love.

Marcus is a man who lives by his own rules, too.  Foregoing his duty as Earl of Renn, he seeks his own destiny in the ancient texts of the Egyptians.  Mary is the only one who understands him and loves him for who he is, and that's not something he takes lightly.  The death of his sister has opened up old wounds and old secrets that must be dealt with first.  This is a story about love that defies convention of the times, to believe in yourself and who you are, and taking risks when the outcome is uncertain.  Ms. Ashworth's gift of exploring the depths of a person, past the layers of pretense, is what makes WHEN IT'S PERFECT a beautiful read.  With breathless love scenes and quick paced writing, it will keep the pages flying.