The Family of Blood ( TV story ) The Family of Blood was the ninth episode of the third series of " Doctor Who " . It featured the Doctor ' s return from his human persona John Smith to his original Time Lord identity . The episode also showed the extent of the Doctor ' s ruthlessness when pushed to extremes . Synopsis . It ' s 1913 , and war comes to England a year early as the terrifying Family hunt for the Tenth Doctor . Plot . As the Family holds Martha Jones and Joan Redfern captive , John Smith is helplessly bewildered by their demands . Tim Latimer briefly opens the watch containing the Doctor ' s essence , confusing the Family with the Doctor ' s scent . This allows Martha to grab a gun from Mother of Mine , take her hostage and point the gun at Son of Mine , who doesn ' t take her seriously and remarks on her fire . Martha snarls " And you can shut up ! " , punctuating the warning with a shot through the roof . Son of Mine doubts that she ' d have the gall to shoot him , but she points out that a scared person with a gun is quite dangerous . The Family members unwillingly lower their weapons and Martha tells Smith to evacuate the building . After everyone has left , Martha releases Mother of Mine but keeps her weapon poised to shoot ' Sonny - boy ' if they try anything . Advancing on her , Son and Mother of Mine remark on her bravery and how Mother of Mine should have taken her form instead . Martha asks about Jenny ' s fate and Mother of Mine sadistically reveals her last moments ; the possession kills the host in the process , unfortunately . Taking advantage , an animated scarecrow grabs Martha and retrieves the gun . She escapes and runs outside , where she finds Smith and leads him away . The watch still tells Latimer to keep it hidden . Smith , Joan , and Martha race back to the school , where Smith sounds the alarm . Father of Mine investigates Martha ' s past movements while the rest of the Family return to the school . They send Sister of Mine to spy on the school ' s inhabitants . Inside the school , Martha pleads with Smith about having the students fight , but Smith says that they are trained to defend King and Country . Headmaster Rocastle enters , angry at first , but approving Smith ' s actions after hearing that Jeremy Baines ( Son of Mine ) and Clark ( Father of Mine ) have gone insane and are chasing them and people have been murder ed . The headmaster and Smith arm the boys and prepare for battle . Unable to stop them , Martha races to Smith ' s room to search for the watch , followed by Joan . Joan slowly comes to accept the origins of Martha and the Doctor . Latimer hides away with the watch . Rocastle and Phillips go outside to assess the situation . Son of Mine demands John Smith be handed over along with his Time Lord consciousness . He mocks Rocastle for teaching children to fight in the war that is coming , which will make them see war as less glorious than they were led to believe . Rocastle states his devotion to King and Country . Son of Mine vaporises Phillips . Rocastle runs back into the school , where Smith and he resume battle preparations . They order the boys to set up barricades and a line of machine guns to repel the Family . Son of Mine summons his scarecrow " soldiers " . Father of Mine finds the TARDIS . Joan asks Smith about his Nottingham childhood , noting that his knowledge is confined to facts . " How can you think I ' m not real ? " he protests . She says that whoever he is , he knows it is wrong to have the boys fight . Sister of Mine finds Latimer , who beams the Time Lord consciousness out of the watch , striking her with an image of the Doctor at his most merciless . This betrays his position and the Family send their scarecrow army to bring out the watch . This army ' s first line is machine - gunned , but Smith finds himself unable to fire . Sister of Mine appears and Rocastle thinks she is merely a girl and should be brought in for her own safety , despite warnings from Martha , Joan and Smith . Sister of Mine kills Rocastle , then taunts the boys , none of whom are willing to kill a girl . Smith orders the boys to make an orderly retreat , but the Family and their scarecrows chase them and line them up to look for the watch . Finding that none of them have it , they are about to massacre the boys when Latimer sends a beam from the watch on an upper floor . This distracts them and the boys get away . Latimer escapes out a window . The Family bring the TARDIS to the school , and taunt Smith , who is watching from the adjoining woods , to come to them . Smith denies having seen the TARDIS before , but Joan recognises it as the blue box in his journal . Seeing this latest evidence of the Doctor ' s existence , Smith pleads desperately to remain himself . The Family return to their ship and use their alien technology to bombard the village to hasten Smith ' s surrender . Smith , Joan and Martha retreat to the Cartwrights ' empty cottage ; Joan has deduce d that Sister of Mine killed her human host ' s parents earlier in the day . Latimer arrives soon after , watch in hand . He says he has seen the Doctor . He calls him fearsome and wonderful . After Smith takes the closed watch , it causes him to speak in the Doctor ' s voice for a moment , explaining Latimer ' s telepathic abilities as due to " an extra synaptic engram " . Smith is horrified . Martha tries to convince Smith to open the watch and change back , saying that she loves the Doctor to bits and he is needed . Smith sees the transformation back to the Doctor as his own suicide . Latimer and Martha leave Joan and Smith alone . Smith has an agonised discussion with Joan . Both see a vision of how Smith will live out his life if he remains human : marrying Joan , having children , becoming a grandfather and dying at home in bed with Joan at his side . Joan remains ambivalent , having discovered from Smith ' s journal the awful consequences of the Family gaining what they seek and how they will spread despair , destruction and death across the universe . Smith appears at the Family ' s ship and stumbles into things as he yields the watch in return for the Family stopping the bombardment ( and , apparently , to preserve his human identity ) . When they open the watch in triumph , they find it empty . Smith has changed back into the Doctor , misdirected their senses so as to seem human and in falling around , pushed buttons which make the machine overheat and destroy itself . Before leaving , he offers them one word of advice : Run ! They quickly oblige and are able to make it out before the ship explodes . The Family and the Doctor escape , but Son of Mine narrates the fate of the Family afterward . He finally realized why this man who had fought gods and monsters had fled from a much less threatening enemy like them : it was a kindness . The Doctor would have preferred that they die peacefully . After all the death they caused , however , instead of showing them mercy he unleashes his wrath and deals out the ultimate punishments to them . As the Family ' s desire was to become immortal , he chooses to grant this wish but in other ways : he traps Father of Mine in chains forged at the heart of a dwarf star , Mother of Mine in the event horizon of a collapsing galaxy and Sister of Mine in every mirror in existence . The Doctor visits her once a year , every year . Finally , the Doctor suspends Son of Mine in time , and dresses him as a scarecrow to watch over the fields of England as its protector . The Doctor visits Joan , who is certain that Smith is dead . The Doctor says Smith still exists within him ; he is capable of everything that Smith was . He invites her to travel with him , but Joan refuses to go with the stranger who wears her dead lover ' s face . Instead she reminds him that had he not chosen to hide then everyone who the Family murdered would still be alive , and sends him away . She watches him leave and starts to cry , clutching Smith ' s journal to her chest . The Doctor returns to the TARDIS , where Martha awaits him . She brushes off her earlier confession as an act of desperation , which he seems to accept . He thanks her for looking after him and they hug . Latimer appears to see the Doctor and Martha off . He states that he now " knows what he must do " and is given the now - empty watch by the Doctor . He watches the TARDIS leave . Latimer later saves Hutchinson and himself on the Western Front , based on his premonition in the previous episode . In the future , when an elderly wheelchair - bound Latimer attends an Armistice Day commemoration , still holding the watch , the Doctor and Martha observe from a distance , wearing poppies . They silently acknowledge each other as the service continues .