Two fifth-graders growing up in post-Civil War California, Mandy McGandy and Jebediah Wu form an unlikely friendship that teaches them about bravery, justice, and the freedom of adventure. Jeb's life in exotic Chinatown and Mandy's on opulent Nob Hill could not be more different. Brought together by the construction of the transcontinental railroad, they face a schoolyard bully, torrential floods, a terrifying train wreck in the Sierra Nevada, and witness the rebirth of their nation.