Defence is the hardest part of bridge and it demands a trust in partnership understandings about leads, suit signals as well as using any information you might get from the bidding. This board showed this and Ian and I did not get it right allowing Bill and George to make 2S plus one when it might have been 2S minus one. However, it is very difficult to find at the table and took a bit of working out even afterwards. East has to start with the singleton 7D won by partner's Ace. West has to assume it is a singleton and return his smallest diamond- a clear suit signal preference for clubs- which east can ruff. Now the tricky part - east has to underlead his AC twice to put his partner in twice for two more ruffs before declarer can get in to claim the remaining 7 tricks. One down and a very satisfied/smug  pair of defenders!