Detailed account of where one was? (10)
I believe the answer is:
exposition
'detailed account' is the definition.
(an exposition is an explanation of something)
'of where one was?' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is located in the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
'was?' could be 'ex' (I've seen this in other clues) and 'ex' is found within the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for exposition that I've seen before include "Account" , "commentary" , "large show" , "Public display" , "fair" .)