A piece of sky tells the story of the resistance of a group of women prisoners and female factory workers. In prison, Joanne questions the authority of those detaining her. Meanwhile, the past catches up with Claudine, working on the production line at the factory, a past which closely binds her to Joanne. Joanne’s lawyer asks her to reveal what drove her friend to violence: accepting to testify would mean denouncing the union structure that still seems to be protecting her. The drama shifts between the factory and the prison, between the personal and the political. Joanna at first relents, cracks and then finally finds within her the strength to forevermore proclaim her right to dignity and the dignity of the women around her. Claudine stands up for herself. She accepts to testify, leading the struggle in the factory, and rejoins Joanna in her radical stance. She refuses the compromise offered by the union structure and accepts the fact of her exclusion. Two women reveal their true selves in their refusal to compromise and are offered an opportunity to renew their friendship.