Thrilling tale: unknown items recorded here? (8,7)
I believe the answer is:
suspense account
'unknown items recorded here?' is the definition.
(banking term)
'thrilling tale' is the wordplay.
'thrilling' becomes 'suspense' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tale' becomes 'account' (I've seen this in another clue).
'suspense'+'account'='SUSPENSE ACCOUNT'
Can you help me to learn more?
(Another definition for suspense account that I've seen is " Where money may be held".)