CHAPTER XVIII.

  THE MAN BEHIND THE DOOR.

  It was a second later that the puff of the exploding rocket reached theears of those gathered about the boxes on the island, for sound does nottravel as rapidly as light. When it came, Lieutenant Carstens made adash for the side of the mountain and began the ascent. After tenanxious minutes he was back again with a malevolent grin on his face.

  "The gunboat has captured the _Manhattan_," he said, facing Ned.

  Ned made no reply, for he was not a little puzzled at the remark. Itindicated that the speaker believed that he had as complete control overthe actions of those on the gunboat as he had over the conduct of thoseon board the _Clara_ and the _Martha_. If this was true, there wasnothing more to hope for. The gunboat would bring Pat, Jack, and Jimmieback as prisoners, and the drum-head would deal with five prisonersinstead of two.

  The Lieutenant now dispatched a man to the shelf of rock on the mountainwhich Ned had previously occupied, instructing him to report theprogress of the gunboat, supposed to be bringing in her prize. From timeto time the watchman called out that the two boats were rapidly nearingthe harbor, and Ned listened to the reports with varying emotions. Nowhe was certain that the officer in charge of the gunboat wouldunderstand the situation; now he was almost sure that the officer andCarstens had had an understanding with each other from the first.

  Two chiefs, evidently men of distinction among the native tribes, nowapproached the Lieutenant and spoke to him in Spanish. After replyingCarstens turned to the son of the senator.

  "Clem," he said, "perhaps you would better bring the box from the cabin.These men are satisfied with the goods they have received, and are readyto sign."

  And so the treaty was to be executed there--after the receipt ofsufficient arms and ammunition to make the revolt against the governmentformidable. Ned saw the craft with which the game had been played, andwondered if the officer who was coming on the gunboat could be inducedto make an examination of the boxes on the beach and the box about to bebrought from the cabin.

  If he could, that would end the trouble so far as Ned and his companionswere involved in it. If he stood hand-in-glove with Carstens, however,he would pretend to doubt the statements offered by the prisoners andrefuse to make any investigation at all. In this case, there was likelyto be murder done before morning.

  "Gunboat rounding the point!" called the lookout.

  The critical moment was near at hand, and Frank and Ned looked into eachother's faces with apprehension in their eyes. Still, there was noweakening, no outward sign of the mental commotion within.

  Presently the gunboat rounded the point to the north and slid into theharbor between the Tusks, followed closely by the _Manhattan_. Ned sawthat the boys were still on the _Manhattan_, but that two men in uniformwere there with them. It looked to him as if the lads had been placedunder arrest, for they did not appear as jubilant as they woulddoubtless have looked if their story had been taken at its full facevalue.

  Lieutenant Carstens appeared to be astonished and decidedly out oftemper when the commander of the gunboat stepped out on the north Tusk.He was nervous, too, and cursed roundly at one of the men who crossedhis path as he advanced to meet the officer. The three boys, who did notnow act like prisoners, flocked off the _Manhattan_ and gathered aroundNed and Frank. Their faces, however, still showed anxiety rather thanjoy at the success of their efforts to bring the gunboat to the island.

  "I presume you have your instructions regarding the _Manhattan_ and hercrew?" Lieutenant Carstens said, after the formalities had been gonethrough with.

  "I understand that the boys took the boat out without permission," wasthe reply. "I am ordered to return her to Manila and to place the boysunder arrest."

  This was encouraging, for Ned knew that they would be safer under theguard of the captain of the gunboat than that of Carstens. Everythingcould be explained if they were taken back to Manila, and not shot likedogs, without a trial.

  "Since leaving Manila," Carstens went on, "they have attacked severalnative settlements and murdered several persons. I already have themunder arrest for piracy."

  "What is the proposition?" asked the other.

  "In my judgment they should be tried here, and, if convicted, executedat the scene of their latest crime."

  "I protest against that," said the other.

  "See here, Curtis," Carstens said, roughly, "these fellows are myprisoners, and I am here with special orders. That will be all."

  "Hardly all," was the cool reply, "for I have my gunboat in the harbor."

  Encouraged by this statement, Ned stepped forward and raised his boundhands.

  "May I speak a word?" he asked.

  "Certainly not!" said Carstens.

  "Go ahead!" the captain of the gunboat, Frederick Curtis, said."George," he added, addressing an officer, "go to the boat and train herguns on this delightful party."

  Carstens turned deadly pale but smiled, and saluted.

  "I'm sure you will do nothing rash," he said.

  "I shall not overstep my instructions," was the reply. "What have you tosay?" he continued, facing Ned.

  "I want a few words with you in private," was the reply.

  "I protest!" shouted the Lieutenant.

  "Best speak here," was the decision of the captain.

  At this moment the senator's son made his appearance on the Tusk with asteel box under his arm. He advanced quickly to the group and passed thebox to Lieutenant Carstens.

  "First," Ned began, "I ask you, Captain Curtis, to take charge of thebox just given to Lieutenant Carstens."

  Captain Curtis extended his hand for the box, but the Lieutenant drewback.

  "This is unusual," the lieutenant said, "irregular and discourteous."

  "I waive the point for the present," Captain Curtis said, "but I insistthat the box shall not leave your hands until it passes into mine."

  "Next," Ned went on, encouraged by the words and manner of CaptainCurtis, "I want you to have the cabin of the _Clara_ searched."

  Lieutenant Carstens approached the speaker in a threatening manner, butCurtis stepped in front of him.

  "Why shouldn't the cabin of the _Clara_ be searched?" the latterdemanded.

  "You shall pay for this indignity!" Carstens roared, turning away fromthe group, with the box still under his arm. Ned pointed to the box, andCaptain Curtis stopped him.

  "I want that box," he said, calmly.

  Lieutenant Carstens hastened his steps and lifted the steel box in hishands, as if about to toss it into the sea. Before he could execute hispurpose, however, the box was seized by the Captain.

  "If you wish to assist in the search of the cabin," Captain Curtis said,"we will go there together. Come along, Nestor," he added, turning toNed and cutting the cord which held his wrists. "You suggested the move,and you shall see what is discovered in the search."

  The Lieutenant moved along with the others, but paused at the head ofthe stairway leading down into the little stern cabin.

  "I protest against this!" he roared, his face bloodless with passion orfright.

  "By the way," Captain Curtis said, lifting the steel box high in theair, "this appears to be quite heavy. Suppose we open it here?"

  "There is no key," Carstens replied.

  Ned held up the odd-shaped key he had found on the island first visited.

  "I think I can open it," he said, "but you'll find that Carstens has akey if you'll take a look through his clothes."

  "Will you surrender the key?" asked Captain Curtis of the Lieutenant.

  "The boy lies!" thundered Carstens. "I have no key."

  "What does the box contain?" asked the Captain.

  "I don't exactly know," Ned replied, "but it is my opinion that itcontains a treaty pledging certain tribes to unite in rebellion againstthe United States provided they are supplied with guns and ammunition."

  "Your opinion is of little account!" gritted the Lieutenant.

  "And I belie
ve," Ned went on, "that other papers are in the box--papersgiving a history of the plot, also papers stolen from the government.Anyway, if you say so, Captain, I'll open the box with my key and we'llsoon find out."

  "Perhaps we would better retire to the cabin," suggested Captain Curtis,noting the curious faces gathering about. "We can settle the wholematter there."

  Lieutenant Carstens would not have entered the cabin if one of theofficers of the gunboat had not crowded him down the stairway.

  "This is an outrage!" he shouted.

  The senator's son now came hastily down the steps, his face red withrage, his fingers working convulsively, as if already playing about thethroat of an enemy.

  "That box is mine!" he cried. "I demand that it be returned to meunopened. I am the son of a United States senator."

  "If what I suspect is true," Ned said, "you will need all the politicalpull a member of the senate has in order to keep yourself out of thepenitentiary."

  "Put that boy out of this cabin!" snarled the young man. "This is myprivate room. I paid for its use during the cruise."

  Ned whispered a few words to the Captain, and the latter turned with asmile to a door opening at the rear of the little room where the excitedgroup stood.

  "Well," he said, "there is a question here as to whether the boxcontains any treasonable documents. If the box belongs to you, open itand we'll see if the charge is true or false. If it is false the boxshall be returned to you."

  "I have lost my key," was the reply.

  "How long ago?" asked Ned.

  The young man turned a supercilious face on the boy, but answered:

  "Several days ago. What is it to you?"

  "Where were you when you first missed it?" Ned persisted.

  "That does not concern you," was the reply.

  "If you lost it in Captain Godwin's station," Ned said, with a smile, "Ipresume I have it."

  He held up the key he had found on the river bank, among the bushes, onthe morning following the abduction of Lieutenant Rowe, and the otherlunged for it.

  "Never mind!" Ned laughed, dodging away, "I don't care to part with thekey just now. After the investigation of the box is over you may haveit."

  "Unlock the box," ordered the Captain.

  Ned stepped forward with his key, but was brought to a stop by a beatingon the door of the rear cabin.

  "I forgot," the boy said, "and the man in there doubtless desires hisliberty. If some of you will unlock the door you will find the man thegovernment sent away in charge of this expedition."

  "What do you mean?" asked the Captain, while Carstens sank back in hischair with a groan.

  "I think," Ned replied, "that you will find the real Lieutenant Carstenson the other side of that door."