- You may be looking for the planet.
When the TARDIS makes a disastrous landing in the swamps of the planet Sunday, the Doctor has no choice but to abandon Martha and try to find help. But the tranquility of Sunday's swamps is deceptive, and even the TARDIS can't protect Martha forever. The human pioneers of Sunday have their own dangers to face: homeless and alone, they're only just starting to realise that Sunday's wildlife isn't as harmless as it first seems. Why are the native otters behaving so strangely, and what is the creature in the swamps that is so interested in the humans, and the new arrivals? The Doctor and Martha must fight to ensure that human intelligence doesn't become the greatest danger of all.
After attempting to visit Arkon for breakfast, the Doctor and Martha arrive on the swamp planet Sunday. When the Doctor exits the TARDIS he slips on muddy roots in the swamp. When trying to steady himself he pushes the TARDIS, which slides down a muddy bank and into a lake with Martha inside. The TARDIS sinks, and the Doctor and Martha are separated.
Martha tries to leave the TARDIS, not realising it has been submerged. When she reaches through the TARDIS force field her arm is grabbed by a mysterious creature, and she is pulled away.
The Doctor sees rising smoke, and heads towards it looking for help. On the way he encounters Candy Kane, who is foraging for water pigeon eggs in the Slim Forest. Candy agrees to take him to her people's settlement, and on the way tells him about a great tidal wave flood which wiped out their first settlement (Sunday City), and killed half of the colonists.
In the new settlement the Doctor meets professor Ty Benson and Col, who have been running maze-tests to study Sundayan otter. Pallister, the city's power-hungry de facto leader shows up with armed guards threatening to shoot the Doctor, calling him a threat. The Doctor uses his psychic paper to convince councillor Pallister that he's an "adjudicator", and after Pallister apologises he escorts the Doctor to a private office. The Doctor, with the permission of Pallister, organises a rescue party to retrieve the TARDIS from the lake using ropes.
Candy and Col discuss the otters, who are rapidly gaining intelligence and losing aggression in captivity. Candy suggests they have learned this from contact with humans.
Martha wakes up in an otter's burrow, and discovers four human skeletons. She sees the otters. A tentacle rises from the black water in the burrow and latches onto Martha’s face. It tries to suffocate her. Before she passes out, the Doctor arrives with Ty and some other colonists. The Doctor uses the sonic screwdriver to create a focussed ultrasound blast which causes the tentacle to retreat into the water. With the tentacle gone, the Doctor sees pinpricks of blood in a small pattern on Martha's face.
The Doctor and Ty abandon the TARDIS to take Martha back to the settlement hospital. There, doctor Sam Hashmi treats Martha for hypoxia and tends to her puncture wounds. Meanwhile Orlo, observing otters in the wild, sees a group of otters all simultaneously stop playing and turn to face in the same direction. Following their gaze, he sees the wreckage of One Small Step, the colonists' ship which had been washed away in the flood. Back at the settlement, the Doctor discovers that one of the otters has scratched the shape of the TARDIS into the side of its cage.
At this moment Orlo bursts in and tells everyone he has discovered the wreckage of the One Small Step. He's also seen Sunday City, but swears it was never in that place before. The Doctor supposes that the water level must be falling. It is revealed that a fission reactor containing uranium had been left aboard the ship, and has been sitting in the waters of Sunday since the flood.
Following a conversation with Ty, the Doctor theorises that the tentacled creature must have arrived with the meteor, or the zoologists on Sunday would have discovered it sooner. The Doctor and Ty arrive at the destroyed Sunday City and find that the water level has dropped even further. They follow the water towards the sea to look for the cause of the sudden drop. Meanwhile Col has gone missing, and Candy sets out to find him. She follows his footprints up to the wrecked One Step Beyond, and climbs a ladder to get inside the ship.
Doctor Hashmi continues to tend to Martha, and tests her blood for signs of possible infection. He discovers on the clipboard by her bed that someone has sketched Sunday being held by giant talons. Martha begins having dreams about the tentacle. When she wakes up screaming, she's questioned by Hashmi and Carolina. When doctor Hashmi shows her the picture on the clipboard Martha begins to howl. She gets out of bed and starts to attack Carolina and Hashmi.
The Doctor, Orlo and Ty discover a huge number of otters at the dam which is preventing the flood from retreating. They appear to be dismantling the dam. They're working in a manic frenzy, and moving in a very unnatural way. After Ty captures an otter by using a Tranq gun the other otters all turn and begin running towards her. The Doctor orders Ty and Orlo to retreat, then aims a concentrated ultrasound signal at the advancing otters. The ultrasound physically repels them, and they are unable to get any closer to the Doctor. Before the Doctor leaves the ruins of Sunday City he sees a line of otters walking towards a building, and decides to return later to investigate.
Aboard the One Small Step, Candy follows Col’s trail to the flight deck, where she finds him on the floor with blacked-out eyes, struggling to speak. He tells her, "it’s in my head", saying something is looking for information. He says that it "needs intelligence". As Col tries to get up to leave Candy sees a rope attached to the back of his neck. The rope pulsates, as if drawing fluid from him. Col apologises to Candy, then wrenches the rope from his neck and dies.
The Doctor returns to the new settlement and visits Martha in the hospital. She has been restrained, tied down to the bed, and continues to thrash about. The Doctor blames himself, wishing he’d recovered the TARDIS before going to explore the settlement. Martha has an infection which is making her act "like an animal", and her irises are blacked-out. Doctor Hashmi gives Martha a dose of adrenaline to counteract the effects of whatever is in her system, and she slowly starts to recover.
Outside the hospital the Doctor is confronted by Pallister, who demands an explanation of what the Doctor is up to. The Doctor dismisses him and heads to the zoo lab. There, the Doctor discovers the captured otter has the same red markings Martha got from the tentacle. Then, in the bio lab, the Doctor and Ty discover RNA proteins containing memories in a sample of Martha's blood. This RNA has been making Martha act aggressively and animalistically. The otters had been infected with this too, and rather than becoming more intelligent in human captivity the otters were actually returning to their natural, uninfected states. To see the effects of this RNA for himself, and to better understand the intentions of the tentacled creatures, the Doctor asks Ty to inject him with the RNA.
Martha wakes up, with the adrenaline and antihistamine injections having calmed her reaction to the infection. Hashmi has taken off her restraints, seeing that she is no longer behaving erratically. When she's alone, Martha slips out of bed and leaves the hospital, hoping to find the Doctor. When she steps into the town square, she sees otters moving behind various buildings across the settlement.
The otters invade a council meeting, capturing Eton and then backing Pallister and Dory Chan into a corner.
Martha enters the bio lab and finds the Doctor strapped to a table, growling like an animal. He grumbles: "All of you. Will...be...ME!". Ty discovers that the Doctor is an alien with two hearts. Then the otters break in to the lab, and Martha uses the sonic screwdriver to repel them. She heads to the zoology lab to fetch a tranq-gun, but on her way there she mysteriously disappears, along with 20 other people in the settlement's town square. The sonic screwdriver is later found on the ground in the square.
Candy returns from the One Small Step and tells Ty what she's seen. She mentions seeing Pallister and Councillor Chan being escorted towards Sunday City by the otters.
Martha has been carried away by otters, who put her down in the woods and begin to talk to her. They are surprised to see she has recovered from the infection. Using only the few words they can manage, the otters offer to help Martha if she can help them in return. She agrees, and follows them further into the woods.
Now awake, the Doctor apologises to Ty and Orlo for not being able to help during the otters' attack on the settlement. He says he has discovered that the swamp monsters want to inject information-encoding proteins into the humans to learn more about them. Theorising that they must want to understand the humans for a specific purpose, he decides to venture to the building in Sunday City that the otters were congregating in to see what they’re looking for.
The otters lead Martha to their nest, where they explain that they are under the control of the swamp monster, and want her to help free them from it. They give her a baby swamp monster that they've found, before asking her to kill its parent.
The Doctor leads Candy and Ty to Sunday City. They see the settlers the swamp monster has under control, and they are carrying out small tasks under the supervision of the otters. The Doctor attempts to dispel the otters with an ultrasound blast from the sonic screwdriver, but finds that this doesn't work because the sonic screwdriver is full of mud from when it was dropped on the ground. The otters, undeterred, advance on the three. The Doctor sends Candy back to the settlement to warn the others about what they've seen. As the otters get closer they surround the Doctor and Ty, before forcing them to move to the water's edge. Suddenly there is a large splashing sound, and Pallister emerges from the water.
Pallister is dead, his body being puppeted by swamp monster tentacles emerging from the water. Through him, the creature orders the Doctor and Ty to join it, saying "unity is better than diversity". During this confrontation, it tells the Doctor its primary aim is to reproduce, and it aims to use its hijacked human intelligence to do this. When the Doctor blasts Pallister with ultrasound the swamp monster is forced to retreat into the water, taking Pallister with it. The Doctor and Ty are still surrounded by controlled otters, trapped at the water's edge. Then, Martha appears on a hilltop opposite, flanked by the otters who are free from the swamp monster's control.
The free otters charge at the zombie ones, shouting to warn them about "water teeth" coming to get them. This snaps the zombie otters out of their trance, and they all flee away from the water. Realising that the swamp monster's trance can be broken, the Doctor goes to all of the captured settlers and awakens them one by one by whispering in their ears and clicking his fingers in front of their faces.
The Doctor and Martha interview the rescued settlers to learn more about the creature's plans. When Marj Haddon struggles to recall any details, Martha suggests the Doctor gets the patients to project their suppressed memories onto the psychic paper. Through this they learn that the swamp monster is building some kind of machine. After learning that Pallister worked in the ore refinery producing uranium, the Doctor surmises that the creature is getting humans to produce uranium so that it can destroy Sunday in a nuclear blast, projecting itself into space to reproduce across the stars.
Meanwhile Candy had snuck back to Sunday City to look for the remaining captured settlers. Once there she hears the sound of drilling, and realises that the mining deep drill outside of the old settlement has been restarted. Back in the new settlement Orlo hears the same noise, and runs to tell the settlers. The Doctor sends Orlo to keep an eye on the otters at the drill site, then heads to the bio lab where he runs tests on the swamp monster’s proteins. After making some adjustments, he injects himself with the RNA again, but this time does not succumb to the violent effects.
At the drill site, Orlo sees Candy from afar through is monocular. He begins to communicate with her through Morse code. After telling him her plan, Candy walked towards the controlled otters and settlers, attempting to blend in. After passing Eton and Professor Chan, Candy is spotted by the otters who had recovered from the slime monster's control in the settlement labs. They too were sneaking around, and they help Candy disarm the bomb by chewing through its detonating wire. Not realising it's been sabotaged, the controlled settlers drop the bomb into the mineshaft, where it lands without exploding.
Fearing the creature will attempt another detonation, the Doctor, Martha, Ty, Orlo and Candy race to Sunday City's generator station where another power core is stored. When they arrive the swamp monster emerges, carrying the decayed corpse of Pallister, and reaches into the building with its tentacles from all sides.
The Doctor abruptly offers to help the creature, saying he can take it to new worlds on which it can reproduce. The creature accepts this offer, but mistakes it for an invitation to assimilate the Doctor as it had done to Pallister. It wraps its tendrils around the Doctor and begins to smother him. Ty loads a tranq gun with the altered swamp monster proteins the Doctor had made at the bio lab and shoots them at the creature. After the first one fails to penetrate the creature's skin, Ty apologises to Martha and shoots a second one into the Doctor's leg. The injection works – the creature seizes up before exploding in a mess of goo. The Doctor falls to the floor, gasping and smiling, before he faints.
When he comes round, the Doctor explains that he had altered the creature's RNA at the biolab so that it would reprogram its metabolism, causing it to die. It was necessary for him to receive the injection in that moment and not sooner so that the effects of the solution wouldn't wear off before the creature made contact with him. As they all walk back to the new settlement the otters – now free from the creature's control – watch the humans and talk among themselves. They see a bright future for their kind, working in cooperation with the human settlers.
- Tenth Doctor
- Martha Jones
- Candy Kane
- Professor Ty Benson
- Col McConnon
- Dr Sam Hashmi
- Marj Haddon
- Chief Councillor Pallister
- Councillor Dory Chan
- Swamp monster
- The Doctor mentions a previous undocumented trip to Arkon.
- Martha makes reference to Breakfast at Tiffany's, Audrey Hepburn and Strictly Come Dancing.
- Martha describes the hospital in the settlement as a "low-tech Butlins", and also compares it to the Royal Hope Hospital.
- The Doctor refers to Donna Summer, Barbra Streisand and their hit song "Enough Is Enough".
- Moisture adversely affects psychic paper.
- The Doctor jokingly refers to Romana by saying that she "knows everything".
- The Doctor compares the swamp monster's reproduction to that of the Krynoids.
Food and beverages
- The Doctor eats an unpleasant breakfast including what the colonists call tomatoes on Sunday.
- Martha eats cheese, fruit and fried eggs on Sunday.
- The Sundayans drank coffee and a tree-sap tea.
- Martha Jones Blog Entry July 1, 2007 referenced this adventure as "the time the Doctor left me stuck in the TARDIS — in a swamp!".
- This story was also released as an ebook available from the Amazon Kindle store.
- This novel was released as an audiobook on 3 March 2008 by BBC Audio and read by Freema Agyeman.
- The adventure takes place after TV: The Family of Blood.
- Martha recalls when the Doctor was possessed by a living sun. (TV: 42)