What does Pi mean?

When Augustus came out of his coma, he began to have those dreams with a lady he can't remember. Augustus also astonished knowing that he has a tattoo, a two-letter word, Pi, in which the meaning is unknown to him.

Until one day, Augustus regained some of his scattered memory, and self-assured that the lady in his dream is real, but the enigma is no one knows her existence.

Who is she?

Is she a nonexistent, a product of his imagination? Or maybe she does exist.

The vagueness of his situation may seem, but one thing is for sure, Augustus will do anything to unleash the truth.