Beam about new story (4)
I believe the answer is:
yarn
'story' is the definition.
('yarn' can be a synonym of 'story')
'beam about new' is the wordplay.
'beam' becomes 'ray' ('ray' can be a synonym of 'beam').
'about' shows that the letters should be reversed in order.
'new' becomes 'n'.
'ray' in reverse letter order is 'yar'.
'yar'+'n'='YARN'
(Other definitions for yarn that I've seen before include "Not fully credible story" , "Fabricated" , "Sailor's tale" , "which could unravel?" , "that'll keep you in stitches?" .)