Sharp dialogue, special effects that hold up fairly well, and a witty, wryly humorous performance by Patrick McGoohan show that Howard Hughes wasn't totally crazy sitting in that Las Vegas hotel room (obsessively watching this, his purported all-time favorite film). Rock Hudson may be the lead, but McGoohan is the real star. His verbal tangles with Hudson over the nature of their secret mission sparkle and give the film most of its fun. McGoohan's portrayal of a somewhat sordid spy who wants to say nothing, and Hudson's as a commander who must know everything, rise above the Cold War story line and give the film an almost timeless appeal. Spare, tight performances from veteran character actors Lloyd Nolan, Gerald S. O'Loughlin, and Ted Hartley help the two leads to shine. Ernest Borgnine's cheerfully amoral Russian defector and Jim Brown's Russian-hating Marine captain mirror the macho fun with their antagonist dialogue, especially when the submarine seems about to sink. (Borgnine: "Captain, if you were to compose your epitaph right now, what would it be?" Brown: "Knock it off.") The film falters in its late section, going with some cheesy special effects -- including Russian planes that are obviously toy-size miniatures, and an indoor polar landscape set -- and the score is redundant at points, but Zebra is a worthy predecessor to The Hunt for Red October, Crimson Tide, and other modern submarine epics.