Wild ocean, sir? That's the story line? (8)
I believe the answer is:
scenario
'the story line?' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'wild ocean sir?' is the wordplay.
'wild' is an anagram indicator.
'ocean'+'sir'='oceansir'
'oceansir' with letters rearranged gives 'SCENARIO'.
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for scenario that I've seen before include "Summary of plot of play" , "Film/novel plot outline" , "Master plan" , "Written outline of a film or play" , "Film plot outline" .)