Robot in Dr No novel brought in to help (7)
I believe the answer is:
android
'robot' is the definition.
(android is a kind of robot)
'dr no novel brought in to help' is the wordplay.
'novel' is an anagram indicator (letters in a new or novel order).
'brought in to' means one lot of letters goes inside another.
'help' becomes 'aid' (synonyms).
'dr'+'no'='drno'
'drno' with letters rearranged gives 'ndro'.
'ndro' going inside 'aid' is 'ANDROID'.
'in' is the link.
(Other definitions for android that I've seen before include "Robot resembling human being" , "Robot resembling 17" , "Being not exactly human" , "artificial being" , "Mechanical man" .)