Spain. Mountain range in Guadarram, overgrown with pine trees. Detachments of Republicans, people's militia climb the mountain path to the firing position. Interbrigade members in the Republican detachment. The soldiers tie a machine gun to the saddle of a mule. Republican soldiers fire rifles at the enemy from a position in the mountains. A signalman in the shelter records the message received by the field communications apparatus. The officers study the battle map and outline the line of fire. The soldiers are firing from an artillery gun. Explosion of a bomb dropped by a Franco plane. The village of Pecherinos in the mountains. The explosion of a bomb dropped by a Frankist bomber on the village. Refugees walk along the road with loaded mules. Refugee children riding a mule. The soldiers carry the wounded on a stretcher, lead the mule across the field, on which the wounded sits. A truck with armed recruits soldiers drives along a mountain road.