Isabella's parents are killed in a fire, and she is sent to live with her aunt in Florence, Italy. Unhappy with this arrangement, Isabella is determined to find a way back to her home in England. She meets a handsome young man named Leonardo, who tells her about a secret passage that leads out of the city. Isabella is hesitant to trust him, but decides to go along with his plan. She is soon caught up in a dangerous adventure that will change her life forever.
Orphaned Sofia is sent to live with her uncle in 16th century Italy and meets Leonardo da Vinci, who she convinces to teach her the art of warfare. The two grow close as they face powerful enemies together.