While not quite an award season darling, one of the more anticipated movies of the next two months is Juan Antonio Bayona’s adaptation of A Monster Calls, a movie about a young boy who dives into a fantasy world to deal with the pain of his sick mother. Part The Iron Giant and part Calvin and Hobbes, A Monster Calls is wholly a film about childhood loss; those who saw the film on the festival circuit have already described it as an earnest tearjerker, including our own Erin Whitney at the Toronto International Film Festival.

In anticipation of this month’s release, Focus Features has now released a brand new featurette (via /Film) on how the crew handled adapting the beloved fantasy novel. In the video, screenwriter Patrick Ness explains some of the tragic history behind the original book  —  the author, Siobhan Dowd, passed away before she could write it, and gave Ness the concept to turn into a fantasy novel  —  as well as the original angle that Ness and Bayona took for the film. According to Ness, Bayona was the one who decided that Conor could be an aspiring cartoonist, thereby solidifying the link between novel and film and giving us an inside look at his imagination.

Here is the full plot synopsis for A Monster Calls from the Focus Features website:

12-year-old Conor is dealing with far more than other boys his age. His beloved and devoted mother is ill. He has little in common with his imperious grandmother. His father has resettled thousands of miles away. But Conor finds a most unlikely ally when the Monster appears at his bedroom window one night. Ancient, wild, and relentless, the Monster guides Conor on a journey of courage, faith, and truth that powerfully fuses imagination and reality.

A Monster Calls stars Lewis MacDougall, Felicity Jones, Sigourney Weaver, and the voice of Liam Neeson. The film will open on December 23 in limited markets and everywhere else on January 16.