Plot way to catch cold (5)
I believe the answer is:
patch
'plot' is the definition.
('patch' can be a synonym of 'plot')
'way to catch cold' is the wordplay.
'way' becomes 'path' (path is a kind of way**).
'to catch' means one lot of letters goes inside another.
'cold' becomes 'c' (eg on taps).
'path' going around 'c' is 'PATCH'.
(Other definitions for patch that I've seen before include "Piece of land, of mending material" , "Mend with extra piece" , "Mend by adding fabric" , "Piece of material used to cover hole in clothes" , "temporary repair" .)