Aemilia Bassano Lanier is beautiful and accomplished, but her societal conformity ends there. She frequently cross-dresses to escape her loveless marriage and to gain freedoms only men enjoy --- and then a chance encounter with a ragged, little-known poet named Shakespeare changes everything.

The two outsiders strike up a literary bargain: they leave plague-ridden London for Italy, where they begin secretly writing comedies together and where Will falls in love with the beautiful country --- and with Aemilia, his Dark Lady. Their Italian idyll, though, cannot last. Will gains fame and fortune for their plays back in London and years later publishes the sonnets mocking his former muse. Not one to stand by in humiliation, Aemilia takes up her own pen in her defense, and in defense of all women.