On the command deck of a gas dredger, Norma Kelligan hears the voice of her dead husband in her head. She is brought back to reality by her first officer, David Nkoto. The cargo thruster is ready to launch. She contacts the refinery and coordinates with Hendryk Koopmaan to launch the thruster. The ship shakes as the view screen shows the thruster explode.
In the TARDIS, Evelyn thinks her headache comes from the stress of their recent adventure, but when both the Doctor and the TARDIS are affected as well, the Doctor realises they are being bombarded by a psychic shock.
On the dredger, David and Robbie MacKenzie begin their usual argument about the the Corporation, but Norma stops them and plans to make her report to Mr Hepton of the Corporation. She first needs a report from Hendryk, but on her way to the refinery she is again besieged by the voice in her head, and, when she hears a loud groaning noise and sees a large blue box appear in the corridor, she curls up into a ball.
The TARDIS has landed "on Jupiter", according to the readings, but as the Doctor and Evelyn leave the ship, they realise they are on a spaceship in Jupiter's atmosphere. They find Norma nearby; she suddenly hugs the Doctor, thinking he's her husband. The Doctor disentangles himself, and when Norma suggests that they are Corporation scientists, he plays along. The ship shakes alarmingly and they head back to the command deck, where the viewscreen shows another ship. Norma claims that it's her husband's ship.
In the refinery, Hendryk complains to his assistant, Leonello Felice, that the captain hasn't been down to check on things yet. He heads for the command deck, but on the way a cloud of matter seeps into the corridor and takes the shape of Hendryk's friend. It gives him a vision of great riches and encourages him to go to the airlock.
The group on the bridge monitors the sudden opening of the airlock as Hendryk leaves the ship that way. As part of the ship's defensive procedures, the refinery is cut off from the rest of the ship, trapping Leonello. Norma orders the engineers to fix it, then begins her report to Mr Hepton.
Norma's report is sent telepathically. She informs Hepton about the cargo loss, but doesn't let him know what happened to Hendryk. He tells her that a stream of methane has been detected nearby and orders her to mine it.
The Doctor notices that the navigation buoys aren't working. He brings it on board the ship for investigation. Meanwhile, Norma goes to her cabin, accompanied by Evelyn. Norma tells her that her husband Thom had been a dredger captain but lost his ship and crew. Before the ship was lost, he sent a message stating, "It's controlling me now." The Corporation ruled he was drunk and therefore liable for the loss of ship and crew. As his widow, Norma is required to work for the Corporation until that debt is paid.
Back on the command deck, Norma is in a kind of trance, staring at the screen. The Doctor orders David to set a course away from the ship on screen, but Norma reacts by destroying the helm. The ship heads towards the Great Red Spot. The Doctor suggests evacuating the ship using one of the cargo thrusters.
Most of the crew gets into the thruster, but Evelyn is staying behind with the Doctor and Norma. After the thruster leaves, she realises that Ajay is still on board. He grabs her by the neck and takes her to the loading bay. Norma is shocked that he's been the one attacking her, but learns that it is actually Mr Hepton who is controlling Ajay. Hepton explains that there is a telepathic gestalt entity living in the Great Red Spot. It attacks anything that comes near it. It destroyed Thom's ship. Hepton plans to destroy it, but the Doctor hits Ajay with a blast from the power cables.
Norma and Evelyn go to the command deck to pilot the ship while the Doctor tries to fix the force field. Norma hears the voice in her head again — it's Thom, who was absorbed the entity. He asks her to come to him, and she goes to the airlock and steps out into the storm.
Hepton tries to control the unconscious Ajay, and finally succeeds. He attacks the Doctor, but is in turn attacked by the entity.
Evelyn is trying to understand Norma's death, but the Doctor thinks that the entity has absorbed her and that she is now with Thom. Ajay wakes up and thinks he's hungover.
- Sixth Doctor
- Evelyn Smythe
- Norma Kelligan
- Thom Kelligan
- David Nkoto
- Robbie MacKenzie
- Hendryk Koopmaan
- Leonello Felice
- Mr Hepton
- Ajay Thakrar
- Tracie Wilson
- The Doctor was trying to take Evelyn to 1927 to meet Charles Lindburgh.
- Earth's empire is at war with the Daleks.
- Thom's ship crashed into the Great Red Spot.
- Dredger captains maintain telepathic contact with the base on Europa.
- Koopmaan smokes a cigar.
to be added