Passage to Planet X

They trailed a legend through the void, seeking a world of freedom, adventure and wealth. They reached their goal, a planet beyond all planets, a weird land of the Lost—where silent death prepared to strike.
Mark Travers hoisted himself up from the floor. He leaned against the supply locker, rubbed his aching jaw where the big man's fist had just landed, and grinned ruefully.
The big spaceman didn't grin. He faced Mark straddle-legged and snapped, Who are you?
Mark Travers. His smooth gray eyes surveyed the man's bulk. He thought he could handle him, but filed it for future reference when he saw the neutro-gun in the other's fist.
Travers, eh. A blasted stowaway! You come aboard at Marsport?
Obviously.
How?
It was easy, Mark shrugged. Your ship was small, dark, and carried no insignia. I watched your men loading supplies secretly. Furthermore, you hadn't filed your destination with Central Bureau. Just the kind of set-up I wanted.
You know a lot, the big spaceman's eyes went hard. Are you a sneaking I-S-P? Never mind. I'll see for myself! He came a step forward, and his gun got playful with the third button on Mark's plasticoid shirt. Expertly the man's fingers went over him.
Careful, there, I'm ticklish!
So's the release on this trigger, so just stand still.
Mark stood still. The search revealed no papers or identification of any kind.