Various clues he'd lined up. (8)
I believe the answer is:
schedule
'various clues he'd lined up' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'various clues he'd' is the wordplay.
'various' indicates an anagram.
'clues'+'hed'='clueshed'
'clueshed' is an anagram of 'SCHEDULE'.
Can you help me to learn more?
(Other definitions for schedule that I've seen before include "You don't see loafers on this" , "Programme or timetable of planned events" , "Plan of times and events" , "Timetable of planned events or work" , "List of intended events and times" .)