Damned If You Don't.

It begins with footage from a stylish old potboiler about an isolated convent, whose tale of passions leashed and unleashed provides the leitmotif for a young lesbian who watches it and the lonely nun she pursues and seduces. As the two women's lives come closer to joining, voiceovers from the biography of a 16th century lesbian nun and the reminiscences of a woman's closeted romances at a Catholic school flesh out the theme.