No homeseekers were ever plagued with more bad luck than those who followed the Englishman John Charles Beales to southern Texas late in 1834. On the banks of Las Moras Creek, not far from the Rio Grande, they established the colony of Dolores. Among them were the British-born Sarah Ann Horn and her husband and two small sons. For the pretty Sarah Ann, who shared her neighbors' fear of Comanche raids, the year or so in Dolores was a preview of a special hell to come. The threat of an invasion by Santa Anna, an uncongenial climate, a lack of trees for lumber, an unnavigable river, crop...