Solo conclusion goes back to princess who helped Theseus (7)
I believe the answer is:
ariadne
'princess who helped theseus' is the definition.
The definition suggests a singular noun which matches the answer.
'solo conclusion goes back' is the wordplay.
'solo' becomes 'aria' (I've seen this before).
'conclusion' becomes 'end' (something's conclusion is its end).
'goes back' says the letters should be written in reverse.
'end' backwards is 'dne'.
'aria'+'dne'='ARIADNE'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for ariadne that I've seen before include "who helped her man with a clue" , "Woman abandoned by Theseus" , "She helped Theseus kill the Minotaur" , "-- auf Naxos, opera by Richard Strauss" , "Strauss role" .)