Legendary weapons in truth cleaned out: fails to secure enough? (12)

'legendary weapons' is the definition.
Although both the answer and definition are plural nouns, I don't understand how they can define each other.

'truth cleaned out fails to secure enough?' is the wordplay.
I cannot really see how this works, but
'out' could be 'under' (I've seen this in another clue) and 'under' is found in the answer.
'secure' could be 'bolt' (I've seen this in another clue) and 'bolt' is found within the answer.
This explanation may well be incorrect...

'in' acts as a link.

Can you help me to learn more?