Partner is famous for his wild preempts - at least NV. Opponents are intermediates.
He leads the ♠4 (3rd / 5th - not low) - low. You decide to rise A and declarer ruffs.
Declarer lays down the ♣Q - 2 from partner (udca).
Declarer crosses to the ♦A....4 from partner
and leads a low heart from the board.
Your play.