 In the series finale, "The Sound of Drums" and "Last of the Time Lords", in which The Doctor's nemesis The Master (John Simm) takes over planet Earth, capturing both The Doctor and fellow companion Captain Jack Harkness (John Barrowman), Martha manages to escape by teleporting away but is left alone to save the world.On the run from The Master, she spends a year travelling the world in a plan which restores the incapacitated Doctor and reverses time, undoing The Master's actions.Able to remember the events during The Master's reign, Martha then leaves the TARDIS of her own accord, telling The Doctor that she cannot waste her life pining for someone when the relationship cannot happen, but promises that she will see him again.