North led the ♣2 South won the Ace and returned their 4th best 7. Declarer played their two low clubs while N won the 8 and then after some thot, shifted.
+50 turned into -460 and a bottom.
Looking back at the spots, I am not sure the position is that readable. How does N figure out that the queen is dropping or should S play some other club? Was this unlucky" Is there some different card S should return to avoid this?
Plus... it's free!