Soon after the novel opens , their 500-strong band -- inspired by the call to arms of Texas ' president , Sam Houston -- heads for the Rio Grande , preparing a sortie to avenge an attack on San Antonio by Mexican marauders .
Texas /location/location/contains San Antonio
Texas /location/location/contains Rio Grande
RB IN DT JJ VBZ , PRP$ JJ NN : VBN IN DT NN TO NNS IN NNP POS NN , NNP NNP : NNS IN DT NNP NNP , VBG DT NN TO VB DT NN IN NNP NNP IN NNP NNS .
Texas
LOCATION
San Antonio
LOCATION
/location/location/contains
Texas
LOCATION
Rio Grande
LOCATION
/location/location/contains