Hazel and Gus are teenagers who meet at a cancer support group and fall in love. They both share the same acerbic wit and a love of books, especially "An Imperial Affliction", so they embark on a journey to visit an author in Amsterdam.
As a war between humankind and monstrous sea creatures wages on, a former pilot and a trainee are paired up to drive a seemingly obsolete special weapon in a desperate effort to save the world from the apocalypse.
Author P.L. Travers reflects on her childhood after reluctantly meeting with Walt Disney, who seeks to adapt her Mary Poppins books for the big screen.