Dismayed, Tom and Bud stared at each other. Apparently the enemy ship had blanked out their radio communication to all points except the mystery plane.  
"Who are you and what do you want?" Tom said into his microphone.
 
The voice replied crisply, "You'll find out when the time comes!"
 
Tom flicked off his mike and exchanged another worried glance with Bud. "We seem to be in a spot, pal!"
 
"And how! Especially if that crate's armed!" Bud muttered. "But what are they after?"
 
Tom shrugged. "The space plants maybe—or possibly our jet."
 
"Might even be us they want," Bud said. "Got any tricks under your magician's hat?"
 
Tom's brain was already racing to figure a way out. Suddenly he snapped his fingers. "Hey! I almost forgot!" he exclaimed. "Look in the locker, Bud, and see if we have the radio set that neutralizes all interference!"
 
Bud's face brightened. "Now you're talking!"
 
The set had been perfected during Tom's Cosmic Astronauts adventure, in defense against an Oriental enemy's jamming-wave generator. Bud found it in the locker, dragged it out joyfully, and plugged it into the power supply.
 
Meanwhile, the mystery jet had banked in a wide circle and headed west. As Tom stalled for time, it swooped back again and the same voice came snarling over the speaker.
 
"I warned you to follow us! Or would you prefer to be shot down?"
 
As if to back up the threat, a burst of tracer fire grazed Tom's plane.
 
He hastily switched on his mike. "Okay, hold your fire! I guess we have no choice!"
 
The jet turned back on its westerly course, and Tom followed obediently. Meanwhile, Bud had warmed up the other radio and contacted Enterprises. Tom switched mikes long enough to report their position, course, and speed, adding:
 
"Tell Security to alert Vignall Air Force Base pronto!"
 
"Roger Wilco!" the Enterprises operator responded. Even if the enemy ship detected the call, Tom knew the automatic scrambling device would prevent the message from being understood.
 
Minute after minute, the flight continued. "Where are they taking us?" Bud muttered.
 
"Some out-of-the-way landing spot probably," Tom conjectured. "I wonder how soon those fighter boys will—"
 
Bud suddenly grabbed Tom's arm and pointed to starboard. "There they come, skipper!"
 
Three gleaming specks had just burst through a cloud bank to the north. Closing in rapidly, they were soon visible as Air Force fighter jets, flying in V formation.
 
"Fighter One to unmarked jet!" came the sharp command over the radio. "Can you read me?... You'd better read me, pal! I order you to proceed to Vignall Air Base under our escort or take the consequences!"
 
The mystery pilot, evidently bewildered by the sudden onslaught, made a frantic effort to escape. But the fighters, with almost contemptuous ease, quickly surrounded the plane and forced him to comply with orders.
 
Bud whooped with laughter. "Just a sheep in wolf's clothing, eh, buster?"
 
Minutes later, all the planes, including Tom's, landed at the airfield. Four sullen-faced men, their hands up, emerged from the mystery jet. Military police with drawn automatics herded them to the commandant's office. Tom and Bud followed.
 
"Attempted aerial piracy, eh?" the commandant said when he heard the boys' story. Turning to the prisoners, he snapped, "Who are you, and what's the meaning of all this?"
 
The crew captain, a hard-looking, stockily built man of about forty-five, rasped back, "We have nothing to say."
 
The commandant wasted no words. "Search them," he told the MP's.
 
Their wallets and various other items revealed little. The crew captain was carrying a private pilot's license on which he was identified as "Jack Smith." The names of the others, as shown on identification papers of one kind or another, sounded equally false.
 
"Probably all forged," the commandant muttered, "but we'll check them out."
 
He tried again to glean something from the prisoners, but they replied with sneering evasions. The commandant reddened with anger at their stubbornness. "All right. Take them to the guardhouse," he ordered.
 
As the MP's marched the hijackers off, Tom asked how their case would be handled.
 
"The crime is a federal offense," the commandant explained. "Air Force Intelligence will co-operate on the case, but the prisoners will be turned over to a federal marshal."
 
Tom briefed him on the background of the situation, including the Jupiter-probing missile mystery, then asked, "Could those men be transferred to the Shopton jail for the time being so our own security setup can take a hand in the investigation?"
 
The commandant nodded. "I'll arrange it."
 
As the boys flew back to Enterprises, Bud threw Tom a quizzical glance. "How come you mentioned the Jupiter prober, skipper? Do you think those hijackers were after information?"
 
Tom shrugged. "I'm wondering myself, Bud. If they were, it could mean our enemy hasn't found it yet!"
 
When they arrived at the experimental station, Tom made a full report to Harlan Ames, the slim, dark-haired security chief. Ames listened thoughtfully but was as baffled as Tom.
 
"Are the men Americans?" he asked.
 
"I doubt it," Tom said. "They speak English well enough, but with a faint accent. Somehow, I have a hunch they're Brungarians."
 
Ames whistled. "That could spell trouble, skipper." More than once, Brungarian rebel agents had engaged in brazen plots against America and the Swifts.
 
"Let's hope I'm wrong," Tom said wryly.
 
"Art Wiltessa—and the Navy—called again," Ames added. "Still no luck on the missile search."
 
The gloomy news did nothing to lift Tom's spirits. The next day, hoping to verify or disprove his suspicion, he drove to Shopton Police Headquarters with Harlan Ames. The two talked briefly with Chief Slater, an old friend. Then a turnkey took them to the cell block.
 
The four prisoners had been confined in a single large cell. They seemed tense and angry—as if they had been quarreling among themselves.
 
"Ready to talk yet?" Ames asked. Getting no reply, he repeated the question in Brungarian.
 
Ames's ruse failed. "What language is that?" asked "Captain Smith" mockingly. "Pig Latin?"
 
As his cellmates grinned, Tom's eyes roved over their faces. One man—wavy-haired with penetrating dark eyes—seemed oddly familiar. Why? Suddenly the answer hit Tom like a flash. He resembled Streffan Mirov, the brilliant Brungarian rocket scientist who had tried to oust Tom's expedition from the phantom satellite Nestria.
 
Playing a hunch, Tom said to him, "You know what your government does to rebels and bunglers, Mirov."
 
The man stiffened and paled. "We have not b-b-bungled!" he stuttered angrily.
 
"Shut up, you fool!" their leader shouted.