Child in a new series (5)
I believe the answer is:
chain
'series' is the definition.
(chain is a kind of series)
'child in a new' is the wordplay.
'child' becomes 'ch' (**).
'new' indicates an anagram.
'in'+'a'='ina'
'ina' with letters rearranged gives 'ain'.
'ch'+'ain'='CHAIN'
(Other definitions for chain that I've seen before include "Shackle" , "Coupling" , "Series of connected things" , "Part of cycle" , "restraint" .)