The term SCI-FI'S DOCTOR WHO is a reference to the British science fiction television series DOCTOR Who. The show follows the adventures of a time-travelling alien known as 'the DOCTOR' who explores the universe in a time-travelling space ship called the TARDIS. The DOCTOR is accompanied by a variety of companions and faces a variety of foes while working to save civilisations and help people in need. The answer to this crossword is WHO, which is the DOCTOR's name.