Civilian scientist Jason Eldridge runs the Magnetic Analyzer Computing Synchrotron (MACS), a
vacuum tube computer aboard the United States Navy ship USS
Elmira. He and his friend Lieutenant Ferguson Howard realize that by using MACS to record a roulette table's spins over time, the computer can predict future results. With Eldridge, Howard and Lieutenant Junior Grade Beauregard Gilliam check into a Venice casino's hotel dressed as civilians, defying Admiral Fitch's order that naval officers on shore avoid the casino and wear uniforms. They plan to use signal lamps to communicate with a confederate manning MACS on the
Elmira. At the hotel, dedicated bachelor Howard meets and romances Julie Fitch, the admiral's daughter (though he is initially unaware of her parentage). Eldridge reunites with former girlfriend and heiress Pam Dunstan, who is in Venice to marry another man. The betting system is very effective, and the three men accumulate hundreds of thousands of dollars in
casino chips. The money gives Eldridge the confidence to propose to Dunstan. However, Admiral Fitch sees and investigates their signals. Soon the Navy, the American and Soviet consulates, and Venice city authorities are on alert for a "revolution". Signalman Burford Taylor finds their signal lamp, so the gamblers get him drunk to detain him, but Taylor escapes and reports to the admiral. Julie Fitch tells her father that she and Howard have "got to marry" each other to save him from court-martial. The Soviets accuse the Navy of using MACS to steal from the casino. To avoid an international incident, Howard agrees to intentionally lose all his chips on his last bet, but a brawl breaks out between Soviets, Americans and Italians in the casino over the chips. The movie ends with newlyweds Howard and Fitch celebrating their honeymoon in the hotel. ==Cast==