 The finale 's narrative brings closure to several prominent story arcs created during Davies ' tenure as show runner . In the episode , contemporary Earth and twenty @-@ six other planets are stolen by the Daleks , aided by their megalomaniacal creator Davros and a shattered but precognitive Dalek Caan . As the Doctor ( David Tennant ) and his companion Donna Noble ( Catherine Tate ) try to find Earth , his previous companions Jack Harkness ( John Barrowman ) , Martha Jones ( Freema Agyeman ) , Sarah Jane Smith ( Elisabeth Sladen ) , and Rose Tyler ( Billie Piper ) convene to contact him and mount a defence against the Daleks . In the episode 's climax , the Doctor is shot by a Dalek and begins to regenerate . 
