Billie was busy with the horses when Don suddenly pointed out toward the American men-of-war. "Look!" he exclaimed. "There's something doing." And sure enough there was. Out from behind two of the largest vessels there suddenly darted a number of launches loaded with blue-jackets and marines. In another instant they had headed for the shore, while out behind them trailed the American flag. The boys sprang to their feet and watched the approaching boats with the utmost interest. "There must be a thousand of them!" exclaimed Billie. "More than that," said Donald, as his eyes ran over the oncoming boats. "There's nearer fifteen hundred." "And look there," cried Adrian. "See those two smaller ships moving in toward shore." "What do you suppose they are going to do?" asked Billie, all in a tremor of excitement. "Looks to me," replied Donald, "like they were going to capture the town." "Why, that's war!" from Adrian. "Well, isn't that what we've been expecting? I wish I knew what it all means." As some of the readers may not know what was the cause of the action it may be explained that a German steamship had arrived the night before loaded with arms for Huerta's army. Admiral Fletcher had no right to seize the German ship, so he determined to seize the port of Vera Cruz. Then if the arms were landed they would be in the hands of the Americans. "Well," declared Adrian, "whatever else it means, it means business." "Do you suppose the Mexicans will try to prevent the landing?" asked Billie. "We'll know in a minute, for they are most ashore," said Donald. Donald was right and in another minute a shot rang out followed by a rattle of musketry. "Flash! Flash! Bang! Bang!" spoke the howitzers in the foremost of the launches. Boom! Boom! Boom! came the sound of three guns from the ship nearest the city, which proved to be the _Prairie_. The crash of the six-inch shells as they struck in the city could be heard above the rattle of the rifle fire which had now become continuous. "It's a sure enough battle," cried Billie. "Come on! Let's go down!" and he flung himself onto his horse. "What would you do?" cried Donald, seizing Billie's horse by the bridle. "You'd be killed by the fire from our own guns. This is the best place we could be in while the firing is going on. As soon as our men have driven the Mexicans out of town, then we can go in." "But I want to take a hand in the fun," said Billie. "It's no fun, as you'll find after it's all over. No knowing how many of our boys are being lost, to say nothing of the Mexicans." "Look!" cried Adrian, who had not taken his eyes from the scene in the harbor. "There are a couple of other ships going into action." Billie turned at sound of Adrian's words. Sure enough, there came flashes from more guns, as the _Chester_ and _San Francisco_ moved up into striking distance, although at that time the boys did not know the vessels' names.