The Lost Lamp - The Heart Stones, #0.5

Fourteen-year-old Marianna loves helping her father with his merchant business, whether on his ships or in the stockroom. When her father's most recent acquisition, a map claiming to lead to the fabled lamp of Aladdin, goes missing, it puts her father's reputation and his business at stake. Determined to get the map back, Marianna embarks on a journey to find it. Her search leads her to exciting new places, and she finds unexpected help from a handsome sailor.
But with every new thing they discover, the danger increases, and Marianna is afraid she may have to give up the expedition before the cost becomes more than she is willing to pay.