A prime number is a lonely thing. It can only be divided by itself or by one, and it never truly fits with another. Alice and Mattia are both 'primes' - misfits haunted by early tragedies. When the two meet as teenagers, they recognize in each other a kindred, damaged spirit. Years later, a chance encounter reunites them and forces a lifetime of concealed emotion to the surface. So, these two prime numbers will fight to find a way to be together.