13-year old Lily has locked herself in her room. Her newly single father chooses to finally tell Lily the story of Mary and Max, a tale set in the 1970s about a seemingly random friendship between Mary Daisy Dinkle, a chubby and lonely eight-year-old with a birthmark on her forehead the color of poo who lives in Australia and Max Jerry Horowitz, a 44-year-old obese New Yorker who is soon diagnosed with a newly named disorder, Asperger Syndrome. As pen-pals, they go through their highest and lowest times together, spanning twenty years. But, will Lily see Mary and Max meet before it's too late?