Les frères Dai et Twn sont deux jeunes gallois qui remportent un voyage à Londres pour voir un match de rugby opposant le Pays de Galles à l'Angleterre. En arrivant dans la grande ville, ils sont vite séparés et se perdent. Mais en se cherchant, les deux jeunes hommes se laissent prendre par les nombreuses tentations de la ville comme les femmes, l'alcool, les promesses de gloire...
A race car driver marries a woman for her money and plans to murder her. An old suitor steps in to help her but the driver takes steps to eliminate the rival. But there's a flaw in the driver's plans.
The hero discovers his estranged wife dead and tries to frame her lover for the murder. He becomes involved with the criminals who make various unsuccessful attempts on his life while the police clear up the mystery.
A husband-and-wife detective team look into the murder of one of her friends, whose father--a prominent scientist--has been kidnapped. They find themselves up against a sinister crime organization headed by a mysterious figure known only as "Z".