Hugh Jackman is electrifying in The River, a concentrated, mysterious fish tale of a play. Seeing him onstage in one of Broadway's most intimate theaters confers a sense of privilege upon the audience something akin to having Mick Jagger show up at your cocktail party just to shoot the breeze. You may not believe your luck. Forget the fact that he is too old by a decade or more to be playing a bachelor whose secluded cabin in the woods above a riverbank appears to be date bait for attractive younger women. That fact merely adds another layer of meaning (or confusion, depending on your receptiveness to such matters) to Jez Butterworth's new play, a hairpin turn away from his last Broadway outing, the sensationally funny, wildly overpopulated, anti-capitalist Jerusalem.