At a London auction, Princess Sonia bids against her husband, exiled Prince Victor, for a Corot landscape in which incriminating letters Sonia wrote are hidden, but it is bought by Michael Lanyard, suspected of being the mysterious, international thief "The Lone Wolf." After Lanyard gives Sonia the letters, she divorces Victor, marries Lanyard and dies after bearing their daughter Sonia. Years later, Sonia, who thinks she is the daughter of the Princess' maid, is found by Victor, now the leader of an underworld gang of Oriental crooks and Bolsheviks. Saying he is her father, Victor brings her to his home, hoping to entice Lanyard to make an appearance.

Michael Lanyard, a reformed cracks-man, adopts Adrienne, the daughter of an old friend, and goes to Southampton to attend a party celebrating her engagement to Bobby Crenshaw, the son of a wealthy society couple. The Count and Countess Polinac, international jewel thieves, also attend the party, and Count Polinac forces Lanyard to open the safe containing the jewelry of the guests by threatening to expose Lanyard's criminal past. Lanyard forestalls the count, however, and protects the valuables. The count and countess are arrested, and Michael's secret is kept safe.

Modest picture centering on a blunderous jewel heist aboard an ocean liner.

In this entry in the Lone Wolf series, the first to have a soundtrack, the jealousies of the King and the coquettish Queen are chronicled. When His Majesty learns that his wife has given the ring he gave to her to her lover, the King plans a large ball and demands the she wear the token. As her lover is a military attache, he is not in the palace, and the queen must send her lady-in-waiting to bring it back. En route, the lady meets a thief and they team up. She does not know that he has been dispatched by the King to steal ring from the attache.

The Lone Wolf, an international thief who is expert in dodging the police, is rifling a wall safe when he senses the approach of detectives. Secreting a necklace in a cigarette case, he makes a hasty retreat. In disguise, he climbs to the balcony of another house where a bal masque is in progress and conceals himself in Marcia Mayfair's boudoir. Later he mingles with the guests and dances with Marcia. Lanyard is disclosed as a stranger when detectives force the guests to unmask, but Marcia remains silent while Lanyard replaces the jewels lifted from her bedroom. Lanyard is warned by Detective Crane, who suspects him but has no evidence. A visit to a bohemian resort owned by Morphew, leader of a band of thieves, provokes a heated argument in which Lanyard is threatened; and Marcia and Lanyard barely escape being caught in a raid. Their romance is threatened when Marcia's jewels are again stolen, but Lanyard traps Morphew and his gang and brings them to justice.

A silent film Directed by Stanner E.V. Taylor.

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

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

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.

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