E.L. "Tenspeed" Turner is a conman who has just gotten out of prison. Hard up, he decides to rip off the Mob for a million dollars, only to discover that the mobsters got the money by fencing Nazi diamonds. Meanwhile, accountant Lionel Whitney is reluctantly preparing to marry his fiance Bunny, and E.L. hides the diamonds in Lionel's limo.
Over E.L.'s objections, Lionel takes on the case of an anonymous millionaire who wants to find a missing woman. The trail leads to the Robin Tucker Ballroom, where a man is dead and the missing woman has gone missing yet again.
An attractive woman hires Lionel to find out who is trying to kill her. However, their first suspect, the husband she was having an affair with, takes a dive off the roof, putting them on the trail of the person responsible.
A stockbroker, Marty Huckerman, hires the agency to investigate two investors men who have threatened him after they came up with invalid social security numbers. When Marty turns up dead, the partners suspect he may have been laundering money for a motorcycle gang.
When a computer programmer goes missing, his attractive sister Lola hires Lionel and E.L. to find him, but it's E.L. that becomes romantically involved with her.
E.L. runs a scam on millionaire Chase Davenport to get him to pay $1,000, and then uses the money to have another con artist hire Lionel to investigate Davenport, since Lionel won't take crooked money. However, it turns out Davenport is actually working with the Mob, and wants the partners dead before they turn up his criminal connections.
An old enemy's girlfriend, a lounge singer, comes to the partners for help. Before they can get any information, she's abducted and they have to rescue her.
E.L.'s nephew B.L. rolls into the town, but neglects to tell his uncle that he stole a numbers runner's receipt book and pinned the theft on his uncle.
On Lionel's birthday, his partner buys him a stolen watch as a birthday present. Things get worse when E.L.'s new parole officer prepares to send him back to prison.
Lionel reopens the old Sable Hills murder case of the 40s, and teams up with the retired police detective who handled the investigation. However, when people start shooting tommyguns at E.L. and Lionel, Lionel figures they're getting close to a solution.
When E.L. discovers the cleaning lady is a Russian countess, he arranges her marriage to a Hollywood talent agent so the agent can get a title... and so E.L. can make a $25,000 finders fee. But he and Lionel get involved in assault and robbery when a Russian history professor sends his thugs to get a jeweled dagger from the Tsar.
When an insane man appears to be a cold-blooded killer faking insanity, a judge hires the agency to find out the truth. However, the partners soon discover that the judge isn't a judge, and E.L. is locked up when he infiltrates the psychiatric hospital.
Tenspeed tries to help Lionel impress his visiting parents by setting him up with a better car and a penthouse office. Unfortunately, the car is stolen and the office's last occupant was a diamond merchant who was murdered for an expensive gem that has gone missing.