A quiet building in Angouleme. Clemence Lacombe is a piano teacher. She receives home visit from her former student Mona, who she considers as her own daughter, and offer her hospitality. A scream in the night, Mona disappears. Clemence investigates and will suspect everyone in her building. Her husband Benjamin, psychiatrist, treating her at home. Medication dosage of Clémence increases. Her reason wavers. Several elements trouble her. Is she prone to hallucinations? Or is she the victim of a conspiracy who wants to silence her?

A dying man entrusts 25 million to a young girl's care, but she's afraid of being suspected of theft.

What connects us as people? A shared space. A common interest. A basic drive. Blood. In our teeming city of millions, lives criss-cross in ways both expected and unexpected. The bag lady. The straphanger. The summer intern. The single mom. In a single evening, these familiar characters discover just what it is that connect one to the other, and along the way confront their own deep secrets. transitions is a snapshot of our modern-day lives, played out on the ultimate world stage.

The day begins. Louis, 25, takes a cab to Roissy airport to welcome Lacey, who's arriving from New York.