Heartbeat

Aristide administers honesty tests to his potential pupils and observes their reactions. He ultimately accepts Arlette into his Paris school, recognizing talent in disguise. This initiation sets up the film's tension between crime and conscience.

Arlette resolves to steal only enough to buy into a sham marriage to avoid reform school. She plans to enter the criminal world on terms she can control. This decision foreshadows the series of deceptive schemes to come.

A well-dressed ambassador catches Arlette lifting his stick pin and pulls her into his fancy house. He becomes her first major contact within high society’s orbit. This encounter thrusts her into a glamorous, treacherous world.

Baron Dvorak arrives and teams with the ambassador to plot a scheme: take Arlette to a diplomatic reception posing as the baron's niece. They seek to leverage her misfit status into access to power. The arrangement drags Arlette deeper into deception.

At the reception, Arlette is told to steal the ambassador's pocket watch. She removes a picture of the ambassador's wife from inside it, leaving the watch empty. The ambassador is initially amused by the ruse, not realizing the deeper trouble it signals.

Pierre de Roche drives Arlette home after the reception. He confesses that he loves her, kisses her, and gives her flowers from his garden. He promises to meet her at the train station the next day, when they are supposedly bound for Geneva.

Arlette sneaks back to Aristide's school but is confronted by the suspicious master thief. His suspicions that she freelanced are confirmed, and he throws her out. The school cuts ties with her as she remains entangled in deception.

Arlette decides to say goodbye to Pierre at the train station and confesses everything. Pierre is angry and misses his train, but he ultimately insists that she stay the night at his house and prepares a guest room. The moment deepens their complicated relationship.

The next morning, Pierre's penniless friend Roland arrives to stay while Pierre is in Geneva. Pierre arranges for Roland to sham-marry Arlette in exchange for 10,000 francs. This bargain entangles Arlette further with Pierre's circle.

In Geneva, Pierre becomes jealous and returns, only to find that Arlette and Roland have hired Yves as a butler and bought clothes that Pierre must pay for. The ruse expands, increasing the social stakes and financial risk.

Arlette attends a reception and a reaction ensues when the ambassador's wife sees Arlette's photo in Pierre's watch. The wife storms out, but Pierre finds the moment charming rather than ruinous. The episode thickens the couple's complicated dynamic.

Pierre admits he loves Arlette and weighs the risks to his reputation. The baron suggests that gaining a niece is better than exposing secrets. The film ends with Pierre and Arlette marrying in a grand ceremony.