Heroic tale of half perhaps fleeing outbreak (4)
I believe the answer is:
epic
'heroic tale' is the definition.
(I've seen this before)
'half perhaps fleeing outbreak' is the wordplay.
'half' means to take half the letters.
'perhaps' becomes 'eg' (for example).
'fleeing outbreak' becomes 'pic' (I can't justify this - if you can you should believe this answer much more).
'eg' halved is 'e'.
'e'+'pic'='EPIC'
'of' is the link.
Can you help me to learn more?
(Other definitions for epic that I've seen before include "Long poem set in nice picture" , "eg Beowulf" , "On a grand scale like long poem" , "Impressive scope" , "Of heroic proportions" .)