South will pass.

West will open 1♠ 

North with 18HCPs will doube and plan to bid ♣ s to show a powerful ♣  hand.

East has a choice 3♠ (probably too weak for this),  2♥ to see what is going on, probably too weak for a Jacoby 2N, 4♦ shows a shortage in ♦ s and enough for game (probably the best bid, and 4♠ which is a wide ranging bid, that could make bidding a slam difficult.

Over all of these bids South could bid 4 or 5♦ . No defensive values so this could be a good sacrifice (and it is!) 5♦ goes -3 doubled for 500

Over 5♦ west has a difficult decision, double for penalties or bid 5♠  the optimal decision. It is easier to make over a 4♦ splinter bid by East. Here is some good info on splinter bids.