Galaxy 4 is the first serial of the third season of the British science fiction television series Doctor Who. Written by William Emms and directed by Derek Martinus, the serial was broadcast on BBC1 in four weekly parts from 11 September to 2 October 1965. In the serial, the First Doctor (William Hartnell) and his travelling companions Vicki (Maureen O'Brien) and Steven (Peter Purves) arrive on an arid planet, where they encounter the beautiful but dangerous Drahvins and the hideous but friendly Rills, two crash-landed species in conflict with one another. Both species wish to escape as the planet is set to explode in two dawns, but the Drahvin leader Maaga (Stephanie Bidmead) only wants for her people to make it out alive.