When high school student Clay Jensen receives a box in the mail containing several cassette tapes recorded by his classmate Hannah, who committed suicide, he spends a bewildering and heartbreaking night crisscrossing their town, listening to Hannah's voice recounting the events leading up to her death.

Ten-year-old Auggie Pullman, who was born with extreme facial abnormalities and was not expected to survive, goes from being home-schooled to entering fifth grade at a private middle school in Manhattan, which entails enduring the taunting and fear of his classmates as he struggles to be seen as just another student.