Evaristo y Tony, hermanos indígenas del noroeste mexicano, acaban de graduarse de la educación básica, cuando reciben una tarea de su abuelo: entregar medicinas al otro extremo de la Sierra Tarahumara. Tony y Evaristo, temiendo el largo camino, deciden llevarse el caballo de su abuelo y comienzan un viaje que termina siendo más largo de lo que esperaban.

Evaristo and Tony, indigenous brothers from northwest Mexico, have just graduated from elementary school when they receive an assignment from their grandfather: to deliver some medicine at the other extreme of the Sierra Tarahumara. Tony and Evaristo, dreading the long road ahead, decide to take their grandfather's horse and set off into a journey that becomes longer than they expected.