After a massive potato famine strikes Ireland, thirteen-year-old Johanna Leary flees to Canada with her family. But typhus and other illnesses plague the "coffin ships," so named for the staggering number of immigrants who died enroute. One by one Johanna loses the members of her family -- first her baby brother on the journey over, then her mother in the Grosse Isle fever sheds where sick passengers are quarantined when they reach the port of Québec, and her father soon after. Johanna has only her brother Michael left when she sets foot on Canadian soil. When her brother is mistakenly told that she too has died, he sets off to find their uncle "somewhere in Canada," leaving Johanna to face a new life in a strange land ... totally alone.