Bullied 13-year old Lily has locked herself in her room. Her newly single father doesn't know what to do. Always a storyteller, he chooses to finally tell Lily the story of Mary and Max, a tale set in the 1970s about the 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 the suburbs of Melbourne, 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 as time flies, will Mary and Max ever find a way to meet before it's too late? And will Lily spiral into darkness before understanding the truth about her own history?