One checks, not happy returning to stage (4)
I believe the answer is:
dais
'stage' is the definition.
(type of platform or stage)
'one checks not happy returning' is the wordplay.
I cannot quite see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
The remaining letters 'das' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'to' is the link.
Can you help me to learn more?
(Other definitions for dais that I've seen before include "support for speaker" , "Welshman's" , "stage" , "stepping up here?" , "stands on this?" .)