Unblock?

Neither vulnerable, East deals

Today’s deal is from a team competition, where overtricks are of little value. The meaning of North’s three-spade bid was not clear to East-West. Many experts play that bid as a Michael’s Cue Bid, showing a two-suited hand with hearts and an unknown minor. They inquired and were told, correctly, that the bid asked South to bid three no trump with a spade stopper. This gave East-West a clear picture, before the opening lead, that dummy would probably have a long, running suit and South would have a stopper in spades. South rose with dummy’s ace of hearts on the opening lead in the hope of blocking the heart suit. This would have worked, except that East unblocked his king of hearts under the ace! South led dummy’s king of clubs to West’s ace, but West was only able to cash two heart tricks and the ace of spades. It looked like the defence had gotten off to a good start. What went wrong?