Determined to go down (3)
I believe the answer is:
I believe this clue is a triple definition!
'determined' is the first definition.
'to go' is the second definition.
'down' is the third definition.
(similar in meaning)
(Other definitions for set that I've seen before include "Arrange; a party" , "Fixed; collection" , "Solidify; group" , "Prescribed" , "carriage" .)