Film rights to Sara Pennypacker’s children’s chapter book Pax, which was published on Feb. 2 and currently sits at No. 1 on The New York Times middle grade best-seller list, were acquired by Sidney Kimmel Entertainment, the production company announced in a release Tuesday.

Pax follows a boy named Peter and his pet fox, Pax, who haven’t left each other’s sides since Peter rescued the young fox years ago. When Peter’s father enlists in the military, he forces Peter to release Pax back into the wild. But in his grief, Peter sets out on a journey to find Pax again, as the fox has adventures of his own. Praised as “searingly honest and heartbreakingly lovely” by fellow author Katherine Applegate, the book doesn’t shy away from the pain of loss and war.

According to SKE’s release, Pennypacker sought to explain the devastation of war to children after being “moved by reports of children injured, diaplced, and orphaned by wars around the globe.”

“In its short time in release Sara’s nuanced and poignant novel has resonated with children and adults alike and we are thrilled to have the opportunity to adapt Pax for the big screen,” says SKE President of Production Carla Hacken in a release. “We look forward to having an incredible storyteller like Sara as a partner in this project.”