Watch full movie online. Passion is a musical with music and lyrics by Stephen Sondheim and a book by James Lapine. The story was adapted from Ettore Scola's film Passione d'Amore. Central themes include love, sex, obsession, illness, passion, beauty, power and manipulation. Set in 19th century Italy, the plot concerns a young soldier and the changes in him brought about by the obsessive love of Fosca, his Colonel's homely, ailing cousin.