Spooner's found everything in ruin (8)
I believe the answer is:
downfall
'ruin' is the definition.
(I know that ruin can be written as downfall)
'spooner's found everything' is the wordplay.
I cannot really see how this works, but
'everything' could be 'all' (all things) and 'all' is found within the answer.
This explanation may well be incorrect...
'in' acts as a link.
Can you help me to learn more?
(Other definitions for downfall that I've seen before include "burst of rain" , "Ruin; heavy shower" , "(Cause of) ruin" , "Collapse, ruin" , "Failure (after successful career?)" .)