Tumberos are the inmates of a penitentiary in Buenos Aires. One of them is the famous lawyer, Ulises Parodi, sentenced to 25 years for a murder he did not commit. The power machine he has used so many times to his own benefit has now turned against him, friends and colleagues abandon him and Ulises must fight for survival in jail: a fierce, lonely world, with no friends, no protection but demanding concessions and transactions to let you survive. As time goes by the fight for justice, truth, solidarity and the authenticity of personal ties will turn this protagonist into a very different man, who is able to defend himself in hand-to-hand combat, confront the internal mafias, to be alone for the first time in his life – and ultimately, to change.