One morning at exactly 12:07 (the importance of the time comes clear much later), a giant tree outside young Conor O’Malley’s bedroom window magically comes to life, tearing itself loose from its thick roots and transforming itself into a scary BUG (Big Unfriendly Giant).

The creature — who admittedly resembles Vin Diesel’s Groot on super plant fertilizer — thunders in Liam Neeson’s growly voice, “I’m coming for you, Conor O’Malley!”

And he does.

Not to harm the lad, but to warn him that the monster will return three more times to tell him a story. At the end, Conor must tell the monster a story — his truth.

The first time I saw J.A. Bayona’s dark fairy tale “A Monster Calls,” I did not know that its then-12-year-old star Lewis MacDougall had lost his mother to multiple sclerosis in 2013.

No doubt this loss sharply informed his breathtaking performance as Conor, a troubled British preteen dealing with father abandonment issues, bullies at school and a dying mother at home.

“A Monster Calls” conjures fantasy and spectacle, painting the screen with vibrant, colorful, sometimes dreamy and nightmarish images that pump caffeine directly into our retinas.

Yet, I remained transfixed, not by those images, but by MacDougall’s bluntly honest portrait of a wounded, angry lad in crisis.

“A Monster Calls,” based on Patrick Ness’ 2011 book, begins with a terrible recurring dream in which an earthquake swallows up an old British church, and Conor races to save someone about to fall into the abyss.

His Mum (“Rogue One” star Felicity Jones) comforts him. She appears pale and wan from fighting a tenacious cancer.

Conor misses his dad (Toby Kebbell), who abandoned his family to start another one over in the United States.

So, Conor’s steely grandmother (Sigourney Weaver, mustering a disappointingly tentative British accent) has taken charge of the household. She and Conor don’t get along.

Conor quietly contains his growing anger: anger with Grandma, the cancer, his dad and the three boys who torment him at school.

And so a monster calls on Conor to tell him three stories: wondrous, stylized works of animation rendered with ink and watercolors.

One story twists Prince

Charming cliches into something dark and unexpected.

The second addresses the frailty of faith in the face of desperation.

The third involves an invisible man tired of being unseen.

Each presents a moral conflict with a lesson about life’s often contradictory elements.

“Humans are complicated beasts,” the monster says. “You believe comforting lies when you know full well the painful truth that makes those lies necessary.”

If the big reveal at the end seems a little obvious, that’s OK. The story is more interested in how Conor discovers his truth than what it turns out to be.

“A Monster Calls” marks the third impressive work from Bayona, who has mastered the ability to frighten audiences without scaring the humanity out of his stories.

His 2007 ghost tale “The Orphanage” and 2012 disaster drama “The Impossible” fit nicely alongside “A Monster Calls” in depicting families under siege.

At the start of “A Monster Calls,” Conor and Mum watch the original “King Kong” and witness the giant gorilla fall to his death after being shot atop the Empire State Building.

Was it fair what happened to the poor beast?

Or was it something a young boy couldn’t understand about life until a monster called?