WTTW split the story into two parts, with the break made at the start of episode four as the Doctor bangs on the door of the airlock. [source: ChicagoEpguides]

Intro: To avoid a head-on collision on the highway, one uses the steering wheel. In space, a more sophisticated maneuver may be necessary as The Doctor and Jo will soon demonstrate. But the consequences of their action will be far more complex than they could ever anticipate as we are about to learn in our approach to the "Frontier in Space."

Outro: Uh oh, an airlock sans air is no place for those of us who must breathe it to exist. Who opened the valve? How will The Doctor escape the prison? How will he escape the moon? Tune in next Sunday evening at 11 for the answers in the exciting conclusion of "Frontier in Space." [source: ChicagoEpguides]