question:  What is Bergstrom's relationship with Johnson?
context: Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed. [p 135 ] By CHARLES V. DE VET monkey on his back Under the cloud of cast-off identities lay the shape of another man— was it himself? Illustrated by DILLON HE was walking endlessly down a long, glass-walled corridor. The truth lurked in some corner of his consciousness, but it was not reached by surface awareness. At the first turn he saw that the aisle merely circled the stairway, coming out into the depot again on the other side. It took him only a few seconds to push the case into the compartment, lock it and slide the key along the floor beneath the locker. But the fact that they had been expecting him meant that others would very probably be waiting outside. A tall ruffian, copper-brown face damp with perspiration and body oil, grabbed him by the jacket and slammed him back against the lockers. Bergstrom’s neat-boned, fair-skinned face betrayed no emotion other than an introspective stillness of his normally alert gaze. The office window was open, but it let in no freshness, only the mildly rank odor that pervaded all the planet’s habitable area. The floor beneath Zarwell’s feet assumed abruptly the near transfluent consistency of a damp sponge. The floor continued its transmutation, and Zarwell sank deep into viscous depths. Zarwell grunted acknowledgment and pushed himself to his feet, apparently unaware that his shirt clung damply to his body. The evening meal hour was approaching when he reached the Flats, on the way to his apartment. Yet always, when his mind lost its sleep-induced [p 140 ] lethargy, the moment of near understanding slipped away. He moved in and joined a party of short, bearded men, directing them as they battered at the wall with a huge log mounted on a many-wheeled truck. Zarwell was not the leader of the invaders, only a lesser figure in the rebellion.
output:  Johnson is the man Bergstrom wants Zarwell to help overthrow the dictator.
options:  Johnson is the dictator of St. Martin's where Bergstrom lives.  Johnson is the client paying Bergstrom to retrieve 
  Zarwell's memories.  Johnson is the man Bergstrom wants Zarwell to help overthrow the dictator.  Johnson is Bergstrom's boss.