La Acequia del Rito y la Sierra in the Mora Valley is the highest and most famous traditional irrigation system in New Mexico. It carries water up and over a mountain ridge and across a sub-continental divide, from the tributaries of the Río Grande to the immense watershed of the Mora, Canadian, Arkansas, and Mississippi Rivers. The names and stories of those who created this acequia to sustain their communities have mostly been lost and replaced by myths and legends. Now, when children ask, some parents attribute the task of moving mountains and changing the course of rivers to Juan del Oso, the stouthearted man whose father was a bear.

From the mountains of northern Spain to the Andes in South America, Spanish-speaking people have told ancient legends of Juan del Oso and his friends. In this children's tale, agriculturalist Juan Estevan Arellano and folklorist Enrique Lamadrid share a unique version of a celebrated story that has been told in northern New Mexico for centuries.