Excitedly, one came into banks over opening of fantastic account (4,4,1,4)
I believe the answer is:
once upon a time
'opening of fantastic account' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'excitedly one came into banks over' is the wordplay.
I cannot quite see how this works, but
'one' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
'over' could be 'upon' (I've seen this in another clue) and 'upon' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for once upon a time that I've seen before include "Fairytale opening" , "Formerly" , "Long ago" , "How to start of a children's story?" , "Fairy story opening" .)