From 1875 to 1956, prisoners sentenced to forced labor in the largest agricultural penal colony in Castiadas (Sardinia), reclaimed 6500 hectares of a swamp while fighting malaria. The story is told by interweaving today's beautiful landscapes with historical reconstructions developed from original documents and footage. This documentary brings to light the profound social aspect of a prison system based on re-education, redemption and reintegration into society of all those committed crimes.