Brooke ( The Lady in the Lake ) Brooke was a Proto - Time Lord , grown from River Song ' s DNA , and a companion of the Fifth Doctor . Biography . Creation . Madame Kovarian harvested Melody Pond ' s embryonic DNA in order to grow more children like her . This resulted in the creation of the Proto - Time Lord s , the first batch consisted of seven siblings : Lake , Rindle , Tarn , Wadi , Creek , Stream , and Beck . ( AUDIO : " The Lady in the Lake " ) The second set of siblings included : Brooke , H - One , H - Two , and O . ( AUDIO : " My Dinner with Andrew " , " The Furies " ) Brooke and the other Proto - Time Lords had the ability to regenerate ; however , the exact amount of regenerations they each had was random . ( AUDIO : " The Lady in the Lake " ) Travels with the Doctor and River Song . She had been sent on a mission by Madame Kovarian to kill the Doctor and joined him as his travelling companion . ( AUDIO : " The Furies " ) She shared numerous adventures with the Doctor prior to their arrival on Terminus Prime . ( AUDIO : " A Requiem for the Doctor " ) When River Song summoned the Doctor to Terminus Prime after witnessing the death of what she thought was the last of her siblings , Brooke was present in the TARDIS , leaving River shocked as she didn ' t recognise her , assuming the Doctor would be travelling with someone else at the time . Brooke complimented River ' s name and assured her that they were going to " get along " . ( AUDIO : " The Lady in the Lake " ) The Doctor , River and Brooke visited several places together . ( AUDIO : " The Furies " ) The Doctor took Brooke and River to Vienna in the 18th century where they discovered that Mozart had completed his final piece and decided to investigate this anomaly , while also uncovering a series of murders which involved people corroding from the inside out . She was jealous of River and tried multiple times to get rid of her , which only made River more suspicious of her . She spiked the Doctor ' s tea with Aqua Galacia in an attempt to kill the Doctor with all of her hate for him ; however , River counter - acted the hate with her love for the Doctor and left the Aqua Galacia in his system neutralised . ( AUDIO : " A Requiem for the Doctor " ) Killing the Doctor . They later arrived at the Bumptious Gastropod where Brooke was supposed to meet with Kovarian following her assassination of the Doctor . Brooke was left with amnesia after River used her hallucinogenic lipstick on her , while the Doctor was left without any memories of both her and River . Brooke later shot the Doctor using regeneration inhibitor s leaving him dead without the ability to regenerate . In retaliation , River shot and killed Brooke triggering her regeneration into a new incarnation and revealing her status as a Proto - Time Lord and one of River ' s siblings . ( AUDIO : " My Dinner with Andrew " ) After she had killed once , Brooke found it difficult to stop killing . Once she had returned to Kovarian ' s spaceship , she killed the entirety of the crew on the deck and subsequently blamed this on River Song . She later acknowledged the legend of the Furies , noting how she liked that they would never give up . When H - One became jealous of Brooke being in Kovarian ' s favour , they got into a fight which resulted in Brooke murdering H - One . She attempted to blame this on River also . Eventually Brooke decided to side with River and turn against Kovarian , she took River ' s vortex manipulator and travelled back to the Bumptious Slug where she convinced Andrew Edwardson to take the Doctor ' s place , deceiving him into being killed by her earlier incarnation in the Doctor ' s place . She remained on Kovarian ' s spaceship with H - Two in order to torture Kovarian and attempt to find a way past her neural block . ( AUDIO : " The Furies " )