A rare auction to a Grand Slam. In response to the strong opener 2S showed a 5+-card suit headed by two top honours. North rebid 2NT and South showed his second suit. North set spades as trump, and South cuebid the ace of diamonds. Roman Keycard Blackwood confirmed two keycards plus the queen of spades. North now counted at least five spade tricks, three red suit winners and three clubs. Clubs might play for five tricks, failing which the fifth club might be established with a ruff, and if necessary a diamond ruff in his hand would be the thirteenth trick.
The only possible problem in 7S is a bad trump break. If either opponent has J10xx you are down, but you can cope with a singleton jack or ten in the West hand: cash the king, dropping his honour, then cross to the ace to finesse on the third round. But this is not the real safety play, which caters for J10xxx in East. Start by cashing the ace of spades. If West drops the jack or ten play small to the king, uncovering the marked finesse. If West shows out on the ace you can finesse the eight, return to hand by playing ace and king of diamonds, and play your last trump. East splits his J10, leaving you with K9 over his J6 You have no trump to lead, but play a heart to the queen (you deserve some luck!) and run clubs till East gives in.