Some of the detail are fuzzy. I'm guessing at the auction but we know that South reached 3N.
The defense ran four diamonds. Declarer bared her ♠Q and a heart from dummy.
The defense exited a club and declarer won in dummy. Down to her last chance, declarer led a heart to the T.
When it lost, declarer claimed -1.
The defense calls you over. How do you rule?