Dread-Flame of M'Tonak

A flame of pure thought ... green and unspeakably vile ... thrust from its own supra-dimension into the Solar warp, it found one whose malignance matched its own—and who would bargain with it. Against them—Ketrik, outlawed and alone!
Ketrik came in from Perlac, came fast, using the Frequency Tuner all the way. Now his great bulk came forward in the control-seat, his eyes fastened intently on the dark blue disk of Earth that loomed ahead.
Strange, he muttered. Strange, no Patrollers! I expected an escort at least, if not a challenge!
But no one heard. Ketrik, as always, had come alone. The helio from Mark Travers, recorded on the sensitized receivers at Perlac, had been more than a summons and a plea; it had contained an undertone of urgency. Ketrik had left at once, making the trip from the newly discovered outer planet in record time, thanks to the secret power-unit which the Earth Council still coveted.
The Earth Council remained haughty, adamant. Only six months ago there had been a skirmish beyond Jupiter in which several Earth Patrollers had gone to flaming destruction against the speedy Perlac ships. The Perlac Incident was developing into open, bitter warfare. Venus remained wisely aloof, riding a crest of peace under the reign of Princess Aladdian. And on Mars, Dar Vaajo sat brooding on his ancient throne, silent and watchful.
Maybe I'm being a fool, Ketrik murmured now as he crossed the orbit of Earth's moon. Mark Travers guaranteed me safe landing and full protection—nevertheless—
Weary but still cautious, he switched to the auxiliary rocket-power, then went to work dismantling the Frequency Tuner. In a short time he had jumbled the unit into a confusion of its component parts, and carefully hid it away. He trusted Mark Travers ... but there were others.
As he picked up the grav-beam for his landing, he thought again of Mark. It would be good to see him again after four years. He wondered if the lad's status as Member of Council had changed him any. Even more, he wondered at Mark's urgent message.