Prime numbers are divisible only by one and themselves. These numbers are solitary and incomprehensible to others. Alice and Mattia are both "prime", both haunted by the tragedies that have marked them in childhood: a skiing accident for Alice which has caused a defect in her leg, and the loss of his twin sister for Matthew.

• Offside
• Alba Rohrwacher
• Luca Marinelli
• Aurora Ruffino
• Arianna Nastro
• Tommaso Maria Neri
• Isabella Rossellini
• Maurizio Donadoni
• Roberto Sbaratto