Task: Question Generation
Input (English): Context : ``Mission to the Unknown'', sometimes known as ``Dalek Cutaway'' and also ``Dalek Cutaway-Mission to the Unknown'', is a missing episode of the third season of the British science fiction television series Doctor Who, first broadcast on 9 October 1965. 
Subject : Mission to the Unknown 
Relation : series
Output (English): Which series is Mission to the Unknown apart of?