The Solitude of Prime Numbers
A prime number is a solitary thing: it can only be divided by itself, or by
one; it never truly fits with another. Alice and Mattia are also alone with
their personal tragedies. As a child Alice's overbearing father drove her first
to a skiing accident, and then to anorexia. When she meets Mattia she
recognizes a kindred spirit, and Mattia reveals to Alice his terrible secret:
that as a boy he abandoned his mentally disabled twin sister in a park to go a
party, and when he returned, she was nowhere to be found.