* * * *
The Venture was now moving on an even keel a hundred miles above the surface of the ghostly blue planet. Stilicha handled the controls as they moved at reduced speed around the equator of the mystery world. Gunda Welk swept the terrain beneath with the ‘scope as they sped along.
The cruel, barren mountains swept back and disappeared in the glowing blue haze behind them. They moved on above the endless wastes of faintly shining desert.
'Thought I saw something shiny moving down there,' Gunda exclaimed in a moment. 'My eyes must be playing me trick!'
'Cheerly's ship is what we want to find,' Thorn rapped. 'It's somewhere here. She hasn't had time to lift the radite and leave, considering how fast we followed her.'
Within a few hours, they had completely circumnavigated the equator of the little mystery world. They had seen nothing but the deathly deserts and mountains, wrapped in. the unchanging, shimmering blue haze.
'Run north and circle the planet again midway between the equator and the pole,' Thorn ordered Stilicha.
'It's kind of like looking for a needle in a haystack, hunting one ship on a whole world,' Stilicha muttered.
'This world isn't big. We'll sweep every mile of it if necessary,' Joan Thorn declared.
Soon they were again circling Erebus, midway between the equator and the northern pole. Before they had gone far, Gunda pointed to a black speck on the northern desert horizon.
'Something odd about that black mountain yonder!' she reported from the ‘scope eyepiece. 'It has none of the shining haze over it—the only place I've seen here that hasn't.'
'Steer toward it, but keep high,' Joan Thorn told the old pirate.
'We'll take a look.'
The black speck on the horizon expanded rapidly as the ship rocketed north. It grew into a big black mountain that loomed in solitary majesty out of a wide expanse of the haze-wrapped desert. brooding beneath the star-flecked dark sky.
It was a mountain almost perfectly dome-shaped, the regularity of its outline startling. It was two miles across at the base and a mile in height. It stood out bold and black because none of the shining blue haze hovered over it.
'Queer, the symmetrical shape of that mountain,' Sua Av muttered. 'Is it possible that it is—'
''There's a ship parked on that mountain!' Gunda Welk yelled suddenly in high excitement,
Thorn leaped to the ‘scope eyepiece. The huge, frowning black mass of the domed mountain jumped into close view. Upon the curved, rough eastern side of the great mass, near the top, rested a long, torpedo-like metal shape.
'It's Cheerly's cruiser!' Thorn exclaimed. 'If they landed on that black mountain, it must be the one spot on Erebus where it's safe to land. We're going to land there and seize her ship!'
She swung, her pulses hammering. 'Veer off, Stilicha, and run back toward the mountain from the west at a mile altitude. Cheerly can't have seen us yet. We'll land on the west side of the mountain and take her by surprise!'
The old pirate swung the Venture in a wide detour, and soon they were rocketing low toward the mountain from the west, hidden by the domed mass from the ship parked on the other side. Expertly, the old Martian brought the ship down to a landing on the rough, curved western side of the great mass.
As the blasting roar of the rockets died, Sua Av turned from the instrument she had been manipulating.
'The atmosphere checks as air, but loaded with elements I can't identify without analysis,' she reported.
'We'll play safe and wear our spacesuits,' Thorn declared. 'Come on!'
They hastened down into the midcompartment of the ship. Stilicha's motley pirate crew were waiting there, all of them looking a little scared by the fact that they had actually landed upon the surface of Erebus.
'We're going over the top of this mountain to find and capture Cheerly's ship, Thom rapped to them. 'On suits, everybody! And bring all the dampers we have. There's to be no using of atom-guns unless absolutely necessary, for we don't want to hurt Lann.'
Five minutes later, the big door port of the Venture ground open. Out through the air-lock moved the company of forty women, all in suits and helmets, with Joan Thorn in the lead.
Thorn noted that they stepped out onto a rough jagged surface of black metal. The whole mountain, it seemed, was of black metal, pocked here and there with deposits of glistening ores. The top of the dome-shaped mass loomed starkly against the dusky, starry sky.
Thorn could not repress a tautening of her nerves. This was Erebus, the forbidden world that had claimed so many explorers’ lives since nine centuries ago. From the curving side of the mountain on which the Venture lay, she could look out westward across the barren deserts, wrapped in mysterious, shimmering blue radiance.
The little party was armed with several of the cylindrical dampers that could put atom-guns out of commission, and with atom-pistols belted outside their space-suits. They started up the side of the metal mountain, trudging against a gravitation that was surprisingly strong for so small a world. The Planeteers and old Stilicha led, and beside them ran the space dog, Ool, her green eyes blazing as though she sensed they were on the same world as Lann Cain.
They reached the top of the domed mountain, and Thorn crouched down with her comrades to reconnoiter. Cheerly’ s ship, a long, many-gunned Saturnian naval cruiser with the name Gargol on its bows, lay only a few hundred yards down the curved rough metal slope. They could see a few women in space-suits outside the ship, digging glistening ores from the deposits that packed the metal mountain,
Sua Av's voice reached Thorn by conduction, as the Planeteers crouched with the old pirate and the space dog.
'They're digging fuel-ores for the return trip,' the Venusian muttered. 'They can't have sighted our ship.'
Thorn nodded her glassite helmet tensely. 'Here we go,’ she said, rising to her feet and signaling the pirates behind them. 'Whatever you do, be careful you don't injure Lann!'
The space-suited attackers swept down the rough curve of the mountain in a silent run toward the Saturnian ship. They were half-way to it before one of the diggers there glimpsed them,
Instantly, the woman fired her atom-pistol at them. The little shell struck a woman behind Thorn, a pirate who fell as the blinding flare of energy enveloped her. Thorn swung the damper she carried toward the Saturnian who had fired, and killed her weapon. 'Quick, women!' Thorn yelled, then remembered that their audios were off, and signaled with her arm.
The little pirate band swept fiercely down the metal slope. Out of the ship, Saturnians in space-suits were pouring and leveling atom-pistols. The dampers carried by Thorn and several of her women deadened many of the weapons, but atom-shells from others flared blindingly among the pirates and felled a half dozen women,
Then Thorn and her followers reached the Saturnians. It became a fierce fight at close quarters, shells of atom-pistols flaring and women falling, under the solemn stars of the darkly . The space dog leaped and tore horribly with her great teeth and talons among the enemy. Thorn swung her heavy cylindrical damper as a great club as she and Gunda and Sua Av fought forward.
The Saturnians, appalled by the fierceness of the pirate attack, scrambled back through the air-lock of the ship.
'After them!' Thorn cried, waving her arm in a fierce forward gesture. 'Don't let them get away with the ship.'
Gunda flung the damper she carried, and it jammed the air-lock door. Then Thorn's women were pushing into the ship.
In ten minutes, the fight inside the ship was ended, Taken by surprise, unprepared for an attack, the Saturnian crew had not been able to withstand the rush of Thorn's followers.
A dozen of the Saturnians lying dead, the survivors stood with hands raised in surrender. As soon as the air-lock door was closed and the oxygenerators functioning, Thorn ripped off her helmet and ordered the massed prisoners to take off their helmets also.
As each sullen green Saturnian face emerged to view, Thorn's pulse pounded. But when all
the prisoners were unhelmeted, she felt a shock of bitter disappointment. Neither Jen Cheerly nor Lann were in the ship!
'Where's Cheerly and the boy?' she demanded fiercely of the crestfallen Saturnian cruiser captain.
'Cheerly left here yesterday, taking two women and the pirate boy,' answered the captain sullenly. 'They went toward those mountains westward.'
'Cheerly had located the radite there?' Sua Av cried eagerly. The Saturnian nodded sulkily.
'Yes, after we landed our ship here, Cheerly worked with our spectroscopes until she ascertained that the deposit of radite lay somewhere in, those mountains. She took the boy with her because she, believed he knows exactly where it is, though he said he didn't.'
'Then all we have to do is to wait till Cheerly comes back here with the radite, and grab her!' Gunda exclaimed.
'No, we can't do that!' Thorn cried. 'Cheerly would bring back the radite, but she wouldn't bring back Lann! We've got to go after her!'
'In our ship?' old Stilicha asked eagerly.
Thorn shook her head. 'We daren't. This is the one safe place on Erebus where a ship can land, remember. We'll have to follow on foot, in our space-suits.'
She saw a quick gleam of satisfaction in the sullen eyes of the Saturnian captain. And Thorn's face tightened.
'You will come along with us,' she told the green-faced captain suspiciously.
The Saturnian went livid. 'I won't go!' she gasped, all secret satisfaction gone at once, 'I won't!'
Thorn seized her by the throat. 'Why not?' she harked 'What are you afraid of? What is it that makes you glad at the idea of us going on foot to those mountains?'
The Saturnian was silent, helpless rage and fear contending in her face.
'Tell, or I'll make you walk out there by yourself!' Thorn menaced. The threat crumpled the captain's spirit.
'I'll tell!' she gasped. 'It means a hideous doom if you venture off this mountain without protection. For all the matter of those deserts and mountains out there, all the matter of Erebus except this single metal mountain, is radioactive matter.
'Erebus is a radioactive world. That's the secret the pirate boy knew, that no one else guessed. A ship that landed anywhere except on this mountain would instantly itself become radioactive by induced radioactivity from the soil on which it landed. The same fate would befall an unprotected woman who stepped off this mountain. This metal mountain is the only non-radioactive matter on the whole planet!'