There's one word in that sentence to help you solve today's deal.
West opens with a trump.
South pulls a second round, then leads a diamond from hand. North's two-heart response was a transfer bid, showing five or more spades. The theory is that if the dummy is weak, the opponents can make something. Well, here East or West has to play perfectly to make three of a red suit. After East wins trick three with the diamond king, if he leads a low heart, declarer ducks, wins the next heart, and plays another diamond to West's ace.