XVIII Prize UPC 2008 SHORT NOVEL OF SCIENCE FICTION. A powerful alien specie is devoted to sow life in certain chosen planets in a distant galaxy. Each 802 years, the "planters" return to collect the crop obtained and, after the collection, to annihilate it all. The technologically advanced mankind of Ekumen has colonized with success the Arm of Orion and, after finding traces of the mysterious existence of the planters, they embark upon an inhospitable adventure to find out the reason of their terrible objectives, seeking to survive an end that seems inevitable.