The Boundless Sea ( audio story ) Publisher ' s summary . River Song has had more than enough excitement for a while . Deciding the universe — and her husband — can look after themselves , she has immersed herself in early 20th century academia , absorbed in writing archaeological theses . But when a mysterious tomb is found in a dry , distant land , excitement comes looking for River . Can Professor Song stop any more members of the expedition from dying ? What deadly secrets lie buried within the crypt ? And will British Consul Bertie Potts prove to be a help , or a hindrance ? Plot . The queen of an ancient tribe is being buried alive with her late husband . She protests , but the priest leading the ceremony seals the tomb with her inside . Such is the tradition . In Great Britain , Professor Straiton , an archaeologist , receives a call about a discovery of a 3000 - year - old tomb in Lower Mesopotamia . They discuss whom to send there and decide to ask Professor Song , a visiting professor . However , River Song has no intention of going anywhere . She tries to get some piece and quiet . At the dig near Ur , Colonel Lifford reluctantly asks Daphne Garsington to climb through the narrow opening into the tomb to give the team points on how to better break in without damaging anything . She is a woman and not even an archaeologist , just seconded to the dig from the British Consulate , but she is the only person small enough to get through . Daphne is happy to oblige . Her not - so - secret admirer Archie Ferrers gives her a leg up , and in she goes . At first she is amazed at the wonders inside , but soon she is attacked by moving lights and is lost in the tomb . Having learned the disturbing news on the telegraph , Professor Straiton relays it to River , thinking that now the situation is definitely out of her league . To his amazement , in five minutes she is ready for the trip . She barely makes it to a steamer sailing from Southampton to Constantinople . On the ship , she has to fend off attention of a Bertie Potts , the British Consul in Ur . He happens to know about the tomb because Daphne was sent from his consulate . He was not , however , informed about her fate . After days of sailing , they reach their destination . When the hired driver for River refuses to take her to the tomb because of superstitions and strange sounds from a saltwater dam near the tomb , Bertie offers River his car . He is mortally bored by his consular responsibilities and needs a change of scenery . River reluctantly agrees but insists on driving herself . Their arrival at the dig is marked by awkwardness when Colonel Lifford assumes that only a man can be a professor . River assures him that her gun gives her equal chances against any man . Turns out that most of the archaeologists have left in fear . Only Freeman Lifford and Archie Ferrers remain , the latter is desperately trying to dig a wider opening to save his beloved . River takes over and soon their little team makes a hole sufficient for her to get through . Bertie is skinny enough to fit there too , and is naturally co - opted by River to join her . They too barely have time to contemplate the ancient treasures before Bertie is attacked by some glowing insect - like lights , which seem to be interested in tears and sweat , and then by something human - shaped , wearing Daphne ' s clothes and very thirsty . They manage to hide from the apparition inside the inner chamber of the tomb by operating a lever . Trouble is , it can only be operated from the outside . Worse still , River ' s colt remained there . Apart from the dead king , the chamber contains many dried - up small animal corpses and human remains that soon spring to life and announce that she used to be queen Prim and now she is thirsty . River manages to learn that Prim was buried alive here in the tomb and has been staying semi - alive all this time before burning her to a crisp . River is not , however , sure that this death would be final for Prim . Bertie manages to reach the human part of the monster - Daphne lurking outside . He asks her to operate the lever , but Daphne is too weak . By now River has figured out that the glowing flying things are saline drone s , which are normally used to keep crew of spaceships alive during long trips . They collect salt wherever they can and use it to keep the crew healthy . But the ones in the tomb are malfunctioning and have been keeping Prim alive for the past 3000 years , turning her into a salt - thirsty monster . Since River neither cries nor sweats , Bertie has to do jumps to produce enough sweat for Daphne to be able to operate the switch . But the drones are feeding Prim too . By the time , the door cracks open , Prim is attacking them again . Forgetting his disguise , Bertie laments that River did not bring her vortex manipulator . But there is no time for surprises . While River , with difficulty , keeps Prim away , Bertie squeezes under the door but makes a mistake of letting Daphne touch him . Now he is also contaminated by the malfunctioning saline drones while Daphne is strong enough to leave the tomb . Although severely dehydrated , Bertie manages to operate the switch and let River out too . She picks up her colt and stops Prim with several bullets . The door to the inner chambers closes again . Bertie is already feeling the thirst but manages to explain to River that he was tasked with bringing her to the tomb . This whole adventure was intended as a test for her . But he would not reveal his masters . Before she leaves , he produces a letter addressed to her . River is not fast enough to save Archie from being contaminated by Daphne . She tells Lifford that the couple are not humans anymore and they need to stop them . Meanwhile , spurred by his thirst , Bertie lets Prim out of her chamber . She restores her strength feasting on him and is finally free . To River ' s surprise , however , Prim does not attack . Still , whatever her plan is , River has to stop her . She gets dynamite , tells Lifford to climb some tree and under no circumstances touch either Archie or Daphne and goes after Prim . She manages to talk to Prim , who wants revenge to all the husbands who do this to their wives . Already the infection spreads across the valley . Snakes and scorpions are infected . And there are hundreds if not thousands of human bodies buried all around . River tries to explain that Prim ' s husband is not to blame for what happened to her , that both River and Prim seem to be pawns in some cosmic game . But that only redirects Prim ' s anger to River . Still she manages to persuade Prim to jump into the saltwater reservoir on the other side of the dam . River correctly calculates that the saline drones won ' t know when to stop pumping water into Prim , eventually destroying her . Realising the treachery , Prim tries to drown River with her . The dynamite explodes and salt water floods the valley . Now all bodies contaminated with saline drones , dead or alive , would meet the same fate as Prim . River is saved by Colonel Lifford who did as instructed and , luckily , had a pick she managed to hold on to . He laments that the whole dig with tomb and everything is now washed away , but River doesn ' t think this to be a loss to archaeology : the tribe ' s history was manipulated by forces unknown . She tries to minimise the damage by providing the colonel with a plausible explanation : there was an epidemic of desert sickness , with hallucinations and all . He is the only survivor . She asks him to notify the next - of - kin of Archie , Daphne and Bertie . On the way back , she concedes that trouble would find her no matter how she hides . She is ready to pursue the mystery further by accepting the invitation in Bertie ' s letter , the invitation to a social event at an unspecified venue , but with temporal - spatial coordinates for pick up somewhere in the Magellan Cloud .