One Last Promise by Amy Corwin Martha

Love defies all obstacles to unite childhood friends…

Bespectacled and plain compared to her two sisters, Martha Stainton cherishes no expectations, except, perhaps, to one day become a doting aunt. After the death of their beloved father, Martha and her two sisters must leave their home and become dependents of their aunt in London. But Martha doesn’t want to leave—or lose her childhood friend, Quinton, now Lord Ashbourne.
On the eve of their departure, an unfortunate death during a dinner party brings Quinton to Martha’s door with a request to put to use her understanding of chemistry. She must analyze samples of the food and drink served to the unfortunate guest, apparently a victim of gastric upset.

With a heavy heart, Martha grants this last request and strives to make Quinton’s final memories of her pleasant. When her investigation reveals that their friendship has turned into something far deeper than a childhood bond, Martha learns that exposing a murderer and leaving behind the man she loves is far more difficult than she dreamed possible.