Get back again at three the evening after (8)
I believe the answer is:
retrieve
'get back' is the definition.
(I've seen this before)
'again at three the evening after' is the wordplay.
'again' becomes 're'.
'at' says to put letters next to each other.
'three' becomes 'tri' (prefix meaning 'three').
'the evening' becomes 'eve' ('eve' can be a synonym of 'evening').
'after' says to put letters next to each other.
're'+'tri'+'eve'='RETRIEVE'
(Other definitions for retrieve that I've seen before include "Get or bring back something" , "Get back (lost item)" , "Find and bring back" , "Win back" , "Recover" .)