Storyteller's rung up (4)
I believe the answer is:
liar
'storyteller's' is the definition.
(I've seen this before)
'rung up' is the wordplay.
'rung' becomes 'rail'.
'up' says the letters should be written backwards (in down clue: letters go upwards).
'rail' backwards is 'LIAR'.
(Other definitions for liar that I've seen before include "Not a truth-sayer!" , "not straight [one]" , "Teller of untruths" , "man of fiction?" , "Perjurer" .)