Millie Sinclair is a socialite from Newport, Rhode Island, a place rich with history—not that she cares. After failing a history test, she's desperate for extra credit and accepts an assignment to tour one of the famous Newport mansions.

At first the old mansions are nothing more than venues for weddings and charity events to Millie. Until she discovers a link to her family history and unearths a world of lies, betrayal and heartache in the pages of her great-grandmother's journals. Learning about her great-grandmother's forbidden love through a series of letters makes Millie question her own growing feelings for a boy who isn't her boyfriend.

All dolled up in her vintage dress, Millie attends the most talked about charity event in Newport's high society—The Roaring Twenties Gala. After fainting, she awakes in 1925 where she not only steps into her great-grandmother's t-strap shoes, but into the worst night of her life—the night the journal entries end. Mistaken for her great-grandmother, and without knowing how to get back to her own time, Millie watches her great-grandmother's life unravel as those she trusts are the ones to betray her.