A guide saving good person in danger (2,5)
I believe the answer is:
at stake
'in danger' is the definition.
'a guide saving good person' is the wordplay.
'guide' becomes 'take' (synonyms).
'saving' indicates putting letters inside.
'good person' becomes 'st' (saint).
'take' placed around 'st' is 'tstake'.
'a'+'tstake'='AT STAKE'
(Other definitions for at stake that I've seen before include "Being risked or bet on" , "Being risked, depending on outcome of event" , "Being risked, like money with bookie" , "where many martyrs died" , "To be won or lost" .)