Fast talking conman EL Early Leroy "Tenspeed" Turner hooks up with straight arrow suburban professional Lionel Whitney (who just happens to have a black-belt in Karate and was an Olympic Games pistol shooting competitor) to form a mismatched buddy private detective team.
As Nazis and mobsters pursue Lionel for the diamonds E.L. planted on him, the accountant convinces the ex-convict to come up with a scam that'll get the criminals arrested.
Lionel takes on his first case, tracking down a missing girl on behalf of a millionaire. But he soon discovers that the millionaire wants her dead, and others start dropping dead round her.
Lionel falls in love with a female client, who has hired him to find who is trying to kill her. Meanwhile, E.L. tries to duck a former partner from his past.
E.L. is smitten with Lola Marshall, a beautiful dancer who hires the partners to find her missing brother, a computer programmer who was used in a scheme to liquidate a tax evader's company against his will.
E.L. gets his old partner, Mike McGill, to run a scam to pay Lionel with con money to keep the agency afloat. However, the fake crime that they set up uncovers a real one, and the crooks will do anything to keep it quiet.
E.L. is busy running a real estate scam on an Arab sheik when his nephew B.L. arrives in town. The boy has stolen a numbers runner' book and has convinced the crook that E.L. has it.