Answer
You are on lead against three spades. You lead the ten of diamonds (two, four, Ace).
Declarer leads a low spade. What’s your play (Ace, King, six)? Declarer would have a very unusual weak two bid if, in addition to holding the diamond Ace, declarer had the heart Ace as well, so place partner with the Ace of hearts. This means that you can get the diamond ruff that you hoped for, when you led a diamond initially. The bidding marks partner with a singleton trump, and while that singleton could be the Queen, it’s at least 6:1 that declarer has that card. So you should play a top spade, lead your second diamond, win the next round of spades, and lead a heart so partner can give you a diamond ruff.
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