Mechanical Heart

On Alicia's 7th birthday her parents got into a terrible carriage accident, and died. She should've died as well but one of her father's friends, Harold Crane, saved her. But everything pays a price; for her to be able to live she has given up her heart, arm, eye, and most of all her feelings. A Cyborg.
A girl who was once Royal is now fallen to the slave ranks, as a messenger; she delivers letters around the kingdoms. One day she accidentally opens a package and reads it, shocked, to find it's a plan to assassinate the highest royals son, Lucas Sterling. She quickly puts it back and delivers it, as if nothing happened, but not long after she runs into the spontaneous Lucas, who has been separated from his guards.
She promises to escort him back, and the fact people are trying to kill him slips out.
Now on the run from Lucas' personal guards, the police, pirates, and one crazy bounty hunter Alicia starts to remember some of her past, and Lucas seems oddly familiar and not all of the pieces are adding up? Will she be able to solve the puzzle in time! Or will her delay cause a war between humans and the Mechanicals?