Desperately we ask – no, beg – Charlie not to retaliate (3,4,3,4)
I believe the answer is:
get ones own back
'retaliate' is the definition.
'desperately we ask no beg charlie not' is the wordplay.
'desperately' indicates an anagram.
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'we'+'ask'+'no'+'beg'+'c'+'not'='weasknobegcnot'
'weasknobegcnot' anagrammed gives 'GET ONES OWN BACK'.
'to' is the link.
(Other definitions for get ones own back that I've seen before include "do like The Avengers!" , "even the score?" .)