San Francisco, 1906: Fifteen-year-old Mercy Wong is determined to break from the poverty in Chinatown, and an education at St. Clare’s School for Girls is her best hope. Although St. Clare’s is off-limits to all but the wealthiest white girls, Mercy gains admittance through a mix of cunning and a little bribery, only to discover that getting in was the easiest part. Not to be undone by a bunch of spoiled heiresses, Mercy stands strong—until disaster strikes.

On April 18, an historic earthquake rocks San Francisco, destroying Mercy’s home and school. With martial law in effect, she is forced to wait with her classmates for their families in a temporary park encampment. Mercy can't sit by while they wait for the Army to bring help. Fires might rage, and the city may be in shambles, yet Mercy still has the 'bossy' cheeks that mark her as someone who gets things done. But what can one teenaged girl do to heal so many suffering in her broken city?