Millie Olson would rather imagine life in the 19th century than face her 21st century life. At sixteen, she's already graduated high school and is expected to attend a top college, a challenge she isn't ready to face. While on a summer visit to her grandmother, she finds a diary written in 1865 that sets her history-loving heart on fire. But her grandmother insists she put aside academics to socialize with high school quarterback Zach MacMillan. The last thing Millie expects is a friendship with Zach, but as the sparks fly, she's forced to confront her fears - with a little help from 1865.