The Skull of Sobek ( audio story ) Publisher ' s summary . " Too much perfection ' s dangerous . " On the isolated planet of Indigo 3 , far out in the wastes of the Blue Desert , lies the Sanctuary of Imperfect Symmetry . It is a place of contemplation and reflection . It is also a place of death . Something from another time , from another world , has found its way inside the hallowed walls . Something with a leathery hide , a long snout and sharp pointy teeth . Tick Tock . Here comes the crocodile . . . Plot . In an unknown religious order , Abbot Absolute and Sister Chalice begin a service , reading from “ The Burning of the World ” , the last chapter of “ The Triumphs of Sobek ” . It tells the story of a battle between the Old Prince of Sobek and his would - be heir , Snabb , who fought over the Skull of Sobek and the power it affords . The Prince disinherited Snabb , calling him Snabb the Reckless , and called the skull to witness against him . After the reading , the Abbot tells the brothers and sisters that the sanctuary gates have been barred , and they are alone . With Sister Chalice , he leads them in a prayer for deliverance . One monk , Brother Tangent , secretly calls a colleague named Dannahill , and says he has an hour to find what they seek . Tangent says the monks have had no visions or other signs for days . With Dannahill still on the line , he goes to the forbidden New Hall , which is filled with water . Suddenly it fills with fire , but Tangent is unharmed ; however , suddenly he says “ they ’ re here ” , and then is ripped apart . The TARDIS materialises on a roof overlooking the Blue Desert of Indigo 3 , where the natives have 83 words for the colour blue — possibly a coincidence , as a storm sweeps the desert every 83 years . Lucie notes that the dunes are all the same size and shape ; the Doctor tells her the monks here , at the Sanctuary of Imperfect Symmetry , believe that too much perfection is a bad thing . He warns her that if you wander into the dunes , you will be lost — and thus the sanctuary is isolated . However , Lucie sees and waves to an encampment outside the wall ; but the people shoot at her , forcing her to duck back . With the Doctor , she heads down into the Sanctuary , but they meet an angry blue - faced monk , Brother Proximus , who tells them they are not welcome , as the sanctuary is closed . The Doctor says the sanctuary is under siege , and they are there to help . Sister Chalice and Abbot Absolute try to put Tangent ’ s body back together . As they do so , they debate the “ guests ” outside , and how they are covering up a murder . Absolute proposes that they declare themselves contagious , but Chalice objects , saying it will attract more attention . At that time Proximus arrives with the Doctor and Lucie . Absolute tries to send them away , but the Doctor offers to help , seizing on Absolute ’ s mention of contagion . Reluctantly Chalice lets him see the body . The Doctor quickly identifies the killer as a reptilian predator , which ripped Tangent in half before he was put back together . Chalice interrupts and has Proximus lock the Doctor and Lucie into guest room three — a cell , as it turns out . Escape won ’ t be easy . However , Lucie has nicked Tangent ’ s cell phone , which is wet with water and blood , but still functional . It contains a video of a dark room filled with flames ; when Lucie looks , she finds herself inside the room in the video . She sees something approaching , and screams . The Doctor calls her name , pulling her back to reality , and she tells him about her experience ; the vision included two large attackers with helmets , swords , and tails — and they were not blue . The Doctor finds documents and a message from one Sister Thrift , which point him toward the dead planet of Sobek . Sobek was an empire ruled by a crocodilian race . Thrift asked Tangent to meet her at the New Hall before evening prayers . When the Doctor dials it back , the line to Thrift is dead . Tired of waiting , Lucie begins tying sheets together to escape . Absolute and Chalice are confronted with a vision of the Old Prince , who demands to know who the newcomer is . Absolute tells him about the Doctor . The Prince says that the Skull has chosen the Doctor as its champion for the final battle that approaches . The Prince tells its followers that the time is approaching for revenge , and that Snabb must find his own champion . The monks commune regarding the visions they have all had : the flames of perfection burning the centuries clean . The monks pray for salvation for the people outside . The Doctor and Lucie escape from their cell window via the sheet rope and find no one in the courtyard — but the Doctor hears hints of the monks ’ thoughts . Lucie heard it too , but thought it was thunder — but the 83 - year storm is still two decades away . The Doctor chooses to find the New Hall , commenting that it is the imperfections of life that make things interesting . The Hall contains a “ healing pool ” ; Lucie remembers that Tangent was wet , indicating he died here . They go inside and find the Hall flooded . There is a display of hand weapons , ostensibly from Sobek — they have miniature crocodile jaws on them . Lucie admits to a fear of crocodiles stemming back to a childhood experience with Peter Pan . The Doctor sees Sister Thrift ’ s body floating , and pulls her in — but Lucie sees something in the water , and the room fills with flames . The Doctor hears the Prince calling him down to their world , though he doesn ’ t know who it is . Suddenly the door opens , and the visions cease . Sister Chalice chastises them , but sends another sister , Sister Radiance , to get the Abbot . She sends Brothers Benedict and Alleric to get the body . She tells the Doctor the flames in the sky are apocalyptic prophecies , and that the refugees outside are seeking safety here . The Doctor counters by explaining that the visions are coming from the sanctuary . He asks who she is hiding . The abbot arrives and demands answers , and Chalice tells him about the death of Thrift ; he immediately blames the Doctor and Lucie . Against Chalice ’ s wishes , he orders Proximus to throw the Doctor and Lucie out via the nearest window . Lucie plays on Chalice ’ s sympathies by offering to join the nuns , and thus avoids ejection . The Doctor is thrown out , though the drop is not high enough to be fatal . She then takes Lucie to have her head shaved . . . The Doctor lands on a tent , scaring off a camel , whose owner is angry . The owner asks him how to get into the Sanctuary , but the Doctor only knows how to get out . Using Tangent ’ s communicator , the Doctor makes contact with Dannahill , who saw the Doctor get thrown out . They meet , and the Doctor tells him about Tangent ’ s death . Dannahill asks about Sobek ; the Doctor describes it as a jungle world that fell to a great war . Dannahill agrees , but regards the war as a revolution against slavery and oppression . He says that his job is to hunt down the last fugitives from the royal family , who stole the planet ’ s great treasure — the Great Skull — as they fled . The Skull is not just a relic ; it ’ s a repository of the planet ’ s history and memories , using — according to the Doctor — molecular data encryption . Dannahill admits to working for General Snabb , and says that the clues lead here . The Abbot tells the Prince that the Doctor is out of reach now . In retaliation for Absolute ’ s disobedience , the Prince bites off the abbot ’ s hand . But where will he find a champion now ? Proximus registers Lucie as a sister , but Lucie refuses to shave her head . Proximus leaves it for Chalice to sort out . Lucie questions him about what the Abbot is hiding , but he evades her questions . Sister Apocrypha arrives to shave Lucie ’ s head , and Lucie flees the room . Outside , Dannahill confirms for the Doctor that the Skull is inside the Sanctuary ; scans indicate massive cerebral activity inside . The Doctor theorises that the visions are cerebral emanations “ leaking ” from the skull . Dannahill appeals to the Doctor ’ s love of freedom , and asks him to help them . The Doctor agrees , as this also helps him toward rescuing Lucie . A rope ladder drops from a window , and the Doctor starts to climb it . Before following , Dannahill quietly contacts Snabb and says it ’ s time for Snabb to make his move . Chalice finds the Abbot , who attributes the lost hand to a disagreement with their guests . He refuses to take the time to reattach it , as long as the bleeding has stopped . He intends to try to restore the balance in spite of the looming battle , and Chalice calls him a fool ; she wants to let the fighting run its course , causing both sides to destroy each other . She has put plans in place to that end . Proximus interrupts and tells them Lucie has run off . Lucie returns to the pool and calls out to the Prince , who calls her down into the water . She is surrounded by crocodiles , and finds herself in a vision of the world that was . Chalice admits to the Abbot that she has gone too far . She has allowed the Doctor back inside . The Doctor arrives and thanks her for the rope ladder . He tells her he is here to find the Skull of Sobek , which he insists is real , despite Chalice ’ s objections . He explains that it is the source of the visions , and must be found before worse occurs . The Abbot calls the Brethren to prayer while Chalice explains that Lucie is missing and probably in danger . Lucie is caught up in the vision of old Sobek with its riches , and of the flames that would snatch it away . Soon she is fully in thrall of the crocodiles , and her voice changes to a reptilian growl . The Prince — or rather , the Skull — has chosen her as his champion ; and now Snabb is coming . Lucie will avenge the theft of their world . Abbot tells the monks and nuns of the darkness coming , and shows them his wounded arm . He calls them to prayer , but the Doctor interrupts and challenges him to tell them who he is hiding . Chalice says that the Doctor is searching for the Skull of Sobek , and it is here — the visions are coming from the Skull . Suddenly the room fills with flames . The voice of General Snabb chooses the Doctor to be his champion . The Doctor only reluctantly agrees , to save Lucie . When the flames disappear , the Doctor tells Chalice that the Prince must have the Skull , and that he must recover it . The Abbot interrupts and reads a description of the Skull from “ The Triumphs of Sobek ” , which describes it as three hundred by thirty cubits — far too large to hide . . . or is it ? The Doctor inquires as to who paid for the construction of the New Hall ; Chalice admits it was the Old Prince of Sobek . The Doctor says that the Skull is the structure of the Hall itself . Suddenly shuttles can be heard outside — Dannahill has brought troops . The shuttle engines cause the windows to implode , and the gate is blown open . General Snabb and his crocodilian soldiers invade the Sanctuary , rounding up the civilians . Dannahill promises Snabb that his champion will be there soon . The Abbot confronts Snabb about his violation of the Sanctuary , but Snabb knocks him down . Dannahill identifies the Doctor as Snabb ’ s champion ; Snabb tells him to prepare for mortal combat against the Prince ’ s champion . However , the Prince arrives first to confront Snabb . Snabb offers Dannahill to the Prince as a gesture , and the Prince kills him and eats him . The Doctor reveals that the Hall was built over the Skull , and asks the General to take it and leave . Snabb refuses , and insists that the Doctor win the Skull in combat . The Prince ’ s champion arrives . . . and the Doctor sees that it is Lucie . Her voice is still reptilian . The Old Prince explains that his mind is joined with hers . She is impervious to reason , and the Prince exults in the Skull ’ s choice of her , as she knows the Doctor well . The Doctor refuses any weapons . Chalice prevents the Abbot from intervening . Snabb allows the Skull to show everyone how the conflict began , and a vision begins . . . Within the vision of Old Sobek , the Doctor tries again to reach Lucie , but she attacks him . The Doctor overcomes her and locks her in a cupboard , and he calls out to the Abbot and Chalice . He orders them to destroy the Skull and save themselves , but they refuse to commit violence . He tells them to use the power of prayer , or rather , the resonance of prayer . At the same time , Lucie breaks out of the cupboard , as Chalice and the Abbot try to figure out what the Doctor meant . They gather the Brethren in the New Hall . As Lucie confronts the Doctor again , Snabb and the Prince banter like old friends over the battle . The Doctor tells the reptiles that the Skull is using them both , but they disagree , considering the Skull a god . He assures them that the Skull doesn ’ t care who wins — it only wants an outcome . To thwart the skull , he concedes defeat and declares Lucie the winner . The Prince and Snabb tell him the Skull will only accept a death ; the Doctor , saddened , walks away . At the same time , the prayer gong sounds . The Doctor tells Lucie she has won , but she refuses to accept it , and chases him toward the New Hall . He promises to fight her there . At the Hall , he tells Chalice to continue the chant . Lucie arrives , but her connection to the Skull is interrupted , and her voice reverts to normal . The Doctor says that the prayers are balancing out the darkness of the Skull . Lucie breaks free and throws off her weapons ; the Doctor urges her to concentrate on the chant and remember herself . The Skull tries to penetrate the Doctor ’ s mind , bringing back the visions of flames . He tells the Abbot and Chalice to increase the tone of the chant . The resonance reaches a critical point as the Prince and Snabb arrive . The Doctor taunts them , but they decide that in the absence of champions , they must fight personally . They fight as the room begins to crack — the Skull of Sobek is breaking up . Everyone except the two crocodiles flees the room as it begins to collapse . In the aftermath , Chalice is unwilling to let Lucie resign her admission to the Sisterhood , and counters the Doctor ’ s arguments , insisting that Lucie needs the Sisterhood . The Abbot intervenes , and argues that the purpose of the Sanctuary is to provide balance — and Lucie provides that balance to the Doctor . Reluctantly , Chalice lets Lucie go — but declares that she is still a member of the Sisterhood , and that the Doctor is in her spiritual charge . The Doctor thanks Absolute , and asks how they plan to pay to rebuild the damaged Sanctuary . Absolute says that the fragments of the Skull will make lucrative archaeological relics , even if they require care to handle . He offers the Doctor confession , and the Doctor makes a hasty exit .