In the 1750s, a Spanish Jesuit priest, Father Gabriel enters the South American jungle to build a mission to convert a tribe of Guaran Indians to Christianity and dreams of a society in which natives will live in harmony with the Spanish and Portuguese. But the colonial governors find this vision dangerous; they would rather enslave the Indians than convert them, and they issue orders for the mission to be destroyed. Former slave trader Rodrigo Mendoza may offer the mission their only protection.