In the year 2119 at the Drum underwater mining facility in Caithness, Scotland, Captain Jonathan Moran makes a journal entry about the craft of unknown origin that they located on the lake bed. With visual scans showing nothing, they had no choice but to bring it aboard.The Vector Petroleum representative, Richard Pritchard, argues that it belongs to his company because they bought all assets. Moran finds writing and orders Lunn to bring him a torch. As Lunn gets it, something moves behind him but he doesn't see it. However, he catches a glimpse of a top-hatted figure in the reflection of the panel. When Lunn turns to investigate, he finds nothing there.
Moran and the others examine the writing but it's in a language none of them understand. The chief scientist, Bennett, suggests that it might be alien but Moran doesn't want to hear it. The captain figures that it's some kind of experimental vehicle left behind when they abandoned the site. Meanwhile, inside Pritchard finds a circular pattern on the wall. A top-hatted figure lunges for him and Pritchard backs away as it disappears. The engines activate and Moran shoves Cass out of the way only to be caught in the fire himself. Everyone abandons the hangar as the fire spreads and the base computer initiates safety protocols. They have no choice but to abandon Moran as the hatches close. Pritchard tells them what he saw, just as a ghostly image of Moran appears, mouthing something. The top-hatted figure appears and the two of them advance on the crew.
Three Days Later
The TARDIS materializes in a hallway and the Doctor realizes that his vehicle is unhappy about something. He wonders why it brought them there, and tells Clara that they're in a 22nd century underwater base. They look around and find the mess room, and discover that the place has been torn apart. A knife is embedded in the wall, and the Doctor concludes that there was a fight 7-8 hours ago. There are no bodies and the provisions are gone, and through the viewport Clara notices a flooded village on the lake floor.
The duo moves back into the hallway and see Moran and the figure crouching on the floor. The Doctor hails them and the ghostly figures walk towards them. They stop and stare at the newcomers, and the Doctor figures that they're curious. After a minute, the ghosts turn and walk away. The Doctor and Clara follow them into the hangar only to discover that they've disappeared. Recognizing the ship as alien, the Doctor goes inside and sees the alien writing. The TARDIS doesn't translate it, and the ghosts reappear outside. Clara realizes that they're mouthing something, and the ghosts grab metal weapons from the nearby rack and attack them. The Doctor and Clara run out and the ghosts phase through the door, leaving the solid weapons behind.
In the hallway, the Moran ghost phases through the wall while the other figure emerges from the floor behind them. The Doctor and Clara take a side corridor and the crew is in the room ahead. They open the door and let the newcomers in, and seal the door behind them.The ghosts walk away and Pritchard asks who the Doctor and Clare are. The Doctor flashes his psychic paper and Pritchard sees it as UNIT ID. Bennett figures that they're ghosts but the Doctor insists that they aren't. The deaf Cass signs that one of the ghosts is their former commanding officer, and they don't know who the other figure is. The Doctor says that he's from the planet Trivoli, and the planet's inhabitants aren't violent. Alice O'Donnell explains that the ghosts first appeared after they brought the spacecraft aboard. The ghosts started attacking them and they took refuge in the room... which is a Faraday Cage, impenetrable to radio waves.
The crew argues about who is in charge now that Moran is dead, and Bennett explains that the base used to be a military training site. The dam overlooking the site burst and the area was submerged. Twenty years ago they discovered a massive oil reservoir. The base computer announces that it's morning and O'Donnell tells the Doctor that the ghosts only come out at night. As they go to the hangar, Pritchard explains that they didn't abandon the base because he didn't want to leave the expensive equipment behind. Bennett explains that there's a Faraday Cage on the base because it was lined with lead to protect them from the radiation from the nuclear generator.
The Doctor boards the spaceship and notices a hatch in the floor. Opening it, he discovers empty circuits for the pilot's suspended animation chamber and asks the crew what happened to it. There's also a missing power cell. Cass refuses to let Lunn enter the ship, signing that it's not safe. O'Donnell assures the Doctor that there wasn't time to remove anything. As Pritchard walks away, the Doctor tries to work out what they're up against. They go to the mess room and the Doctor concludes that they're actually dealing with ghosts. Cass points out that Moran was their friend, and Clara has the Doctor read the card commiserating with their loss and promising to help. He's more enthused about the fact that there's life after death and wonders what the ghosts want... just as the power goes out. The base computer announces that they're in night mode, and the cloister bell in the TARDIS rings.
Running to the TARDIS, the Doctor realizes that the TARDIS wants to get away from the ghosts because they're an aberration in time. He activates the braking system and tells Clara to stay inside the ship. Clara insists that she's fine and leaves anyway.
Pritchard returns inside after donning a diving suit. He sees a figure outside the airlock and, assuming that it's Bennett, explains that he went out looking for the missing power cell. Pritchard soon realizes that it's Moran's ghost, who steps forward along with the Trivoli. The company man goes to the viewport and tries to work out what they're saying, and the Moran ghost opens the outer door, flooding the airlock chamber before Pritchard can get his helmet back on.
The crew grabs provisions and in the mess room, Clara and Bennett spot Pritchard… just as his corpse drifts against the viewport. The Pritchard ghost turns toward them as the others run in, and he picks up a chair and advances on them. On the bridge, O'Donnell restores the day cycle, causing the ghost to disappear.
Back on the bridge, the crew brings up the security footage of the ghosts killing Pritchard. Cass suggests that they abandon the base. When the Doctor objects, Cass says that he can stay if he wants but her first priority is to protect her crew. O'Donnell calls Topside and they say that they're sending a submarine to pick them up per their previous request. They explain that someone sent an SOS message in Morse code a half-hour ago, requesting a full paramedic team. The Doctor takes the mike, gives his UNIT ID, and tells them to call back the sub. He warns that they have a dangerous contagion onboard and puts the base under quarantine. The Doctor hangs up and explains that the ghosts want the paramedics there, and says that they have to figure it out on their own.
The Doctor tries to work out why the day cycle holds off the ghosts. Cass says that the diagnostic systems only run during the day, and the Doctor tells O'Donnell to put the base back into night mode so they can find out what the ghosts want. O'Donnell reluctantly does so and Bennett finds the three ghosts in the mess room. They come after him and Bennett runs to where Clara is waiting. When the ghosts go by here, she gets their attention and leads them toward Lunn. Lunn tries to lead them toward a flood door, but Moran and the Tifala go after Clara while Pritchard pursues Lunn. The Doctor has O'Donnell close a flood door to hide Clara, and they continue on.
Lunn enters the chamber and O'Donnell closes the flood door. However, Pritchard sees Lunn before it closes. It phases through the door, grabs a wrench... and then walks away. Lunn tells the others that he's okay, and they spot Bennett on the cameras. The other two ghosts are near him, and the Doctor has him run. The ghosts pursue and Pritchard joins them, and Clara appears ahead in the Faraday Cage chamber. Bennett ducks off a side corridor, and the ghosts enter the chamber... and pass through the Clara hologram. O'Donnell closes the door by remote, and the Doctor comes up and addresses the ghosts through the intercom.
Clara and the others return to the bridge and bring up the cameras in the hallway outside the Faraday Cage. Cass can't get a good look at them through the thick glass viewport, so the Doctor orders O'Donnell to open the door. He points out that the ghosts have no access to weapons or controls and repeats his order, and O'Donnell reluctantly opens the door. Moran reaches into the Doctor's chest, mouthing words, but realizes that he can do nothing to the Doctor. Cass lip-reads the ghosts and translates, saying that they're saying "Freeze. The Dark. The Sword. The Forsaken. The Temple." over and over.
Back on the bridge, the Doctor has Bennett get maps of the area and explains that the ghosts are reciting coordinates. The dark refers to space, and the sword refers to Orion. The forsaken refers to the nearby town. Every time the ghosts kill someone, it strengthens the signal that they're sending out. The Doctor realizes that someone is responsible, killing people, and turning their souls into transmitters. As for the temple, it refers to the flooded military town. There's a church there and the Doctor figures the coordinates are in the church. He says that they can all go, but they dedicated their lives to making a difference and they'll always wonder what the answers are to their questions. Cass says that the crew should go, but she's responsible for what happens so she's going to stay. The others stay with her.
The crew sends the remote sub to the town to investigate the church. They find the suspended animation chamber from the ship and bring it back to the base. It’s deadlocked sealed and the Doctor can’t open it, and he suspects that someone other than the pilot is inside. He tries to work out why the ghosts showed them the spaceship and then tried to kill them, and examines the writing with his sonic sunglasses. The Doctor then asks Cass what one thing is puzzling her. When she mentions the markings, the Doctor says that they’re magnets and they already knew what the words the ghosts were saying meant. The words rewrite the synaptic connections in their brains, and people can’t stop reciting them even in death. The person in the chamber left the words so that people would transmit them, and could wait until someone came to pick him up.
The computer gives an evacuation alert and O’Donnell discovers that a computer malfunction has caused the reactor to seemingly overload. The computer is programmed to open the hull doors to flood the base and cool it. Cass has O’Donnell close the internal flood doors to contain the water in the central corridor... where the TARDIS is located. With thirty seconds left, the group runs for the TARDIS. A door comes down cutting off the Doctor, Bennett, and O’Donnell in the lead from the others on the other side of the central corridor. The Doctor calls to them to wait, warning that he can’t take the TARDIS to them because it won’t go near the ghosts. He promises to go back in time, understand why the ghosts are attacking, and stop them from killing anyone else.
Clara, Cass, and Lunn go back to the mess room.
The Doctor and the others take the TARDIS back in time.
Clara assures the others that the Doctor will come back and save them. They look out the viewport and see a ghost approaching... and realize that it’s the Doctor.
Written by Gadfly on Oct 4, 2015