Novel family appearing in Act 1 (5)
I believe the answer is:
doone
'novel family' is the definition.
(family in the novel Lorna Doone)
'act 1' is the wordplay.
'act' becomes 'do' (to do is to act or execute a task).
'1' becomes 'one' (synonyms).
'do'+'one'='DOONE'
'appearing in' acts as a link.
(Other definitions for doone that I've seen before include "See 2 Down" , "'Lorna - - ': novel" .)