The command room became silent as the underground signal continued to pulse across the tactical display. Vane stared at the readings and checked the signal several times to make sure the system was not producing a false result. "It is definitely inside the northern tunnel network."
Kaelen studied the display. "Distance from the evacuation group?"
Vane brought up the underground map. "About three kilometers."
Eva immediately turned toward the door. "Then we need to warn them."
Kaelen stopped her. "Not yet."
Eva looked back at him. "General, if someone is inside those tunnels, the evacuation group is in danger."
"I know."
"Then why are we waiting?"
Kaelen pointed toward the signal. "Because whoever is transmitting it wants us to notice."
Vane looked at the display again. "The signal is too weak to be accidental."
"Exactly."
Kaelen enlarged the underground map. The northern tunnels had been built decades ago for mining operations. Most of the original passages were damaged, flooded, or blocked by collapsed rock, and only a few routes were still usable. The evacuation group was moving through one of those routes.
Kaelen studied the signal location. "Where exactly is it?"
Vane pointed toward a section beneath the old mining district. "Tunnel Seven."
Eva frowned. "That tunnel was supposed to be abandoned."
"It was," Vane replied.
Kaelen looked at him. "Can you identify the transmitter?"
"I can try."
Vane connected the station's old sensors to the underground network. The display flickered several times before a rough outline appeared. A small signal source was moving through the tunnel.
Eva stared at it. "It is moving."
Kaelen nodded. "How fast?"
"Slowly."
"Toward the evacuation group?"
Vane checked the direction. "No. It is moving toward the surface."
Kaelen's eyes narrowed. "Then they are not attacking the evacuation group."
Eva looked at him. "What are they doing?"
"They want us to think they are."
Kaelen turned toward Vane. "Can you trace the signal without alerting whoever is carrying it?"
Vane considered the question. "Maybe. If I use the old mining sensors instead of the military network."
"Do it."
Kaelen looked toward Eva. "How many fighters are near the northern tunnels?"
"Eight."
"Send four to the evacuation group."
Eva nodded. "And the other four?"
"Keep them hidden near Tunnel Seven."
Eva understood. "You think the signal is bait."
"I think we should assume it is."
She opened the command channel. "Four fighters will reinforce the evacuation group. The remaining four will move to Tunnel Seven and stay concealed."
Kaelen watched the tactical display as the fighters moved into position. A few moments later, Vane looked up. "I have something."
Kaelen moved closer. "What?"
"The signal is not coming from a handheld transmitter."
"What is it?"
Vane enlarged the scan. "It is attached to something much larger."
"How large?"
"About two meters."
Eva frowned. "Two meters?"
Vane nodded. "Possibly a drone."
Kaelen looked at the signal path. "Can you identify its power source?"
"Not yet."
"Keep trying."
The underground signal continued moving through the old tunnel system before suddenly stopping. Vane watched the display carefully.
"It stopped."
Kaelen studied the location. "Where?"
"Directly beneath the old processing plant."
Eva looked at him. "There is nothing there."
"There is always something somewhere," Kaelen replied.
Vane checked the old station records. "The processing plant had an underground service level."
"How deep?"
"About thirty meters."
Kaelen's expression changed. "Show me the entrance."
Vane brought up an old structural map. A narrow service tunnel connected the processing plant to the main mining network.
Eva pointed toward it. "That tunnel is outside our current defensive perimeter."
Kaelen nodded. "Which means anyone entering from outside could reach it without crossing the station."
Vane looked at the signal. "General, the transmitter is active again."
The signal began moving, this time toward the surface.
Kaelen looked at the surface map. "How long?"
"Less than three minutes."
"Everyone stays where they are."
Eva looked at him. "You want to let it reach the surface?"
"Yes."
Vane stared at Kaelen. "Why?"
"Because I want to know what it is trying to find."
The signal continued upward. Ten seconds passed, followed by another ten, and then the sensor showed that it had reached the old service level.
Vane's face changed. "What is it?"
"There are multiple energy sources."
"How many?"
"I cannot get a clear count."
Kaelen looked toward Eva. "Prepare the fighters."
Eva nodded.
The four fighters near Tunnel Seven moved into position. They hid behind damaged support structures and switched off their weapon lights. The station remained quiet while the unknown signal moved closer to the surface.
Then the service entrance opened.
A small machine emerged from the darkness. It was not a normal mining drone. Its body was covered in dark armor, and four thin mechanical legs carried it across the abandoned floor. A small antenna extended from its upper section while a blue sensor moved from side to side.
Vane watched through the station's remote camera. "Military reconnaissance drone."
Kaelen studied it. "Imperial?"
"No."
Eva looked at the drone. "Then what is it?"
Vane scanned its outer structure. "I cannot identify the manufacturer."
The drone stopped near the center of the abandoned processing level. Its sensor slowly turned toward the station.
Kaelen watched it carefully. "It is scanning."
Vane checked the readings. "Power systems, weapons, communication towers."
Kaelen nodded. "It is collecting information."
The drone suddenly released a small pulse.
Vane's display changed immediately. "The pulse just activated something."
"What?"
"I do not know."
Kaelen looked toward the old processing plant.
A low mechanical sound came from beneath the ground.
Eva raised her weapon. "General."
Kaelen listened as the sound became louder.
Vane checked the underground sensors. "There are more signals."
"Where?"
"Below us."
"How many?"
"At least twelve."
Eva looked toward Kaelen. "Those are not drones."
Kaelen shook his head. "No."
The tactical display showed several large shapes moving through the underground tunnels. They were coming from different directions.
Vane's voice became tense. "They are approaching the station."
Kaelen looked at the map. "From where?"
"Tunnel Seven, the eastern service route, and the old water system."
Eva looked toward the station walls. "They are surrounding us from underground."
Kaelen nodded.
The first drone had not been trying to attack. It had been activating the others.
Kaelen looked toward Vane. "Can you shut down the underground network?"
"I can block some sections."
"Do it."
Vane began working.
The station lights flickered as several underground passages disappeared from the tactical display, but the unknown signals continued moving.
Vane shook his head. "They are using their own navigation system."
"Then cut the power."
"I cannot."
"Why?"
"The old mining grid is supplying them."
Kaelen looked at the power map. "How?"
Vane pointed toward the processing plant. "The drone connected itself to the abandoned power network."
Kaelen understood. "They entered through the old mining system."
Eva looked at him. "Can we destroy the processing plant?"
"Not yet."
"Why?"
"Because we do not know what is inside."
Another mechanical sound echoed through the station. This time it came from beneath the eastern wall, and dust fell from the ceiling.
The frontier fighters in the command room looked toward the floor.
Kaelen remained calm. "Everyone to defensive positions."
Eva immediately began giving orders. The fighters moved through the corridors while the station's remaining weapons powered up.
Outside, the unknown fleet continued approaching the planet.
Inside the station, something else was approaching from below.
Vane suddenly looked at Kaelen. "General."
"What?"
"The ships just changed direction."
Kaelen turned toward the tactical display.
The three unknown vessels were no longer moving toward the northern tunnels. They were moving directly toward the station.
Eva looked at the screen. "They know."
Kaelen nodded. "They have received the drone's data."
Vane looked toward the underground signals. "Then the drone was only the first part of the attack."
Kaelen studied the tactical map. "How many fighters are ready?"
"Thirty."
"Keep ten at the northern tunnels."
"And the others?"
"Bring them to the main station."
Eva nodded.
Kaelen turned toward Vane. "Can the orbital cannon fire again?"
Vane checked the power readings. "Not at full strength."
"How much?"
"Twenty four percent."
"Enough for one shot?"
"Maybe."
Kaelen looked at the approaching fleet. "Then save it."
Vane looked surprised. "Save it?"
"We do not know what they are sending first."
Kaelen turned toward the underground display. "And I want that shot available when we know."
A heavy impact shook the station. The eastern wall cracked, and several emergency lights went dark.
Eva looked toward the corridor. "They are through."
Kaelen reached for his weapon. "Where?"
Vane checked the sensors. "Lower maintenance level."
Kaelen looked at the frontier fighters. "Do not let them reach the command room."
The fighters moved into the lower corridor as energy weapons opened fire. The sound of gunfire echoed through the station while Kaelen remained at the tactical table, watching the enemy fleet descend through the atmosphere and the underground signals move closer.
The station had survived the first attack, but the enemy had changed its strategy. They were no longer testing the defenses. They were trying to break the station from the inside.
Kaelen looked at the tactical display. "Vane."
"Yes?"
"Open every old mining map you can find."
Vane brought them up.
Kaelen studied the tunnels. "There has to be another route."
"Another route to where?"
Kaelen pointed toward the deepest section of the underground network.
"Here."
Vane looked at the coordinates. "That area was sealed."
"Why?"
"The records say there was a structural collapse."
Kaelen examined the map. "Do the records say what caused it?"
Vane searched the damaged files. "No."
Kaelen looked toward the corridor where the fighting continued. "Then we find out."
Another explosion shook the station.
The tactical display flickered as the unknown fleet entered the upper atmosphere.
At the same time, a new underground signal appeared.
It was much larger than the others.
Vane stared at the reading.
"General."
Kaelen turned. "What is that?"
Vane slowly shook his head. "I do not know."
The signal moved beneath the station and then stopped directly under the command room.
Kaelen looked at the floor.
For the first time since the attack began, his expression became completely serious.
Something was beneath them.
And whatever it was, the enemy fleet had come to protect it.