"Twelve Bar Blues" is a multi-generational tale that spans across time and continents, intertwining the lives of characters from New Orleans to London and Africa. The narrative explores the roots and evolution of jazz music through the life of a legendary cornet player, his granddaughter who is in search of her roots, and an Englishman obsessed with the history of jazz. The book delves deep into the themes of love, identity, race, and music, presenting a vibrant portrayal of the jazz age and its cultural impact.