A teenage loner pushes his way into the underworld of a high school crime ring to investigate the disappearance of his ex-girlfriend.

Michael Lanyard is suspected of stealing two fabulous diamonds from a vault in Scotland Yard, where they were being held for safekeeping, but the Yard can't prove he did it. Later, Lanyard is summoned by a member of the nobility to help the latter raise money to pay a blackmailer. Lanyard later finds evidence to reveal the diamonds as having been stolen by a famous stage star.

Michael Lanyard's faithful butler Jamison is mistaken for his boss by a gang of jewel robbers.

The Lone Wolf tracks down Nazi spies in London during the German bombing.

A reformed jewel thief fights to clear his name when he's framed for murder.

A hardworking secretary for a rich woman finds herself engaged to the woman's son and accused of a murder she didn't commit.

Spies force former jewel thief Michael Lanyard to steal defense secrets in Washington.

Reformed jewel thief the Lone Wolf investigates the murder of a playboy who was blackmailing three socialites.

Former jewel thief Michael Lanyard toys with a princess and a grand duke.

Complicated plot involving missing stamp collection and kidnapped businessman, with the Lone Wolf keeping one step ahead of the police in Havana trying to solve the crime and make a profit.

Once a jewel thief always a jewel thief? Yes and no. Yes if you consider the fact that Michael Lanyard also known as the Lone Wolf once retired from the "trade" but relapses back into his old habits when he is tempted by the emerald pendant of beautiful socialite Marcia Stewart. The trouble (?) is that he falls for the belle and he soon gets more interested in getting the girl than the jewels that adorn her. What he wants now is to return the pendant but a rival gang interfere and force him to take part in a big-time caper.

Michael Lanyard, aka the Lone Wolf, is sailing to America when he meets pretty Eve de Montalais. Eve wants to sneak her valuable necklace through U.S. customs so that she can use the money from its sale to help straighten out her brother. The only problem is that there is a gang of jewel thieves on board who are just as determined to steal the necklace.