The opposition bid uncontested to 7s,
1d-1s
4d-4n
6c-6h
7s
Dummy showed a solid diamond suit with the Q of trumps and a club void plus one more keycard.
4d showed a solid diamond suit with 4 card support 6-4, 6c showed a club void plus an even number of keycards. 6h asked for the trump queen, and 7s showed it.
What is your lead?
EDIT: Your opposition are ex polish U25 internationals, and extremely good. If that matters to you.

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