ACES ON BRIDGE
When South hears his partner cue-bid two spades, initially a game try, he temporizes with three diamonds. After one more cue-bid from South, North takes control with Blackwood, then bids five no-trump to indicate possession of all the key-cards and the trump queen, and eventually settles for the small slam.
After the lead of the spade king to the ace, declarer draws trumps with the heart king and ace. Now, before testing diamonds, he takes the club ace and king, and ruffs a club in hand. On this trick, West discards a spade, suggesting that he holds at least three diamonds. So declarer cashes the diamond king and leads a diamond to the 10. When East discards, South exits with a spade. West can win, but is faced with a choice of ways to surrender the 12th trick, in the form of either a ruff-and-discard or a diamond lead into the tenace.
If declarer had played the hand in a simpler fashion, just exiting in spades after eliminating the trumps and clubs (as many people would), then he would have survived if West had taken the second spade. Then, if West led a diamond from the queen, the diamond loser would vanish, while if he gave a ruffand-discard, South could ditch one diamond and still be on the diamond guess.
However, the defense would prevail if East could win the spade exit and lead a diamond. West can simply cover South's card and collect a diamond winner at the end, no matter what declarer does.
Answer: Your partner has warned you not to bid on, suggesting some defense against spades. Yes, you have five hearts, but your defense is more than adequate, so you should pass — and lead a trump, of course. On all these auctions, declarer's best chance of scrambling tricks normally comes from a crossruff.