When I was younger, I experienced a pair of recurring dreams. I began having the dreams when I was around seven years old, and continued to have them, on and off, for years after.

In the first of these, I was lying in bed in the bedroom I shared with my younger sister (she was in her bed in the dream), and someone on the other side of the bedroom door was nailing the door shut – more precisely, nailing boards across the door to prevent it being opened. I knew this was happening – I could hear it – and I knew that my mother was on the other side, also aware that I was being nailed in. The dream recurred for years, but stopped recurring when I was still a child.

The other dream was both similar and thematically opposite, but it requires a bit of background to explain. So, in actual reality, when I was about six years old I and my three-year-old sister went exploring down a small hill behind our apartment building. A short distance down, we came to a path that went through a wooded area. We walked along the path for a bit, until we encountered a barking dog. The dog scared my sister, who began to cry, and I threw a stick in the dog’s direction, trying to distract it. That didn’t work, so we turned around and walked back along the path – but we couldn’t find our apartment building. We walked back and forth along the path, failing to find our way home, getting more and more anxious, until finally, in desperation, I led us off the path and straight up the hill. At the top of which we found our building, and my father, waiting on a park bench. I had forgotten that we had walked down the little hill to get to the path in the first place.

So: the dream. In the dream, I would wake up – and I would still be down on that path in the woods. I was still with my sister, still lost – but if I was sixteen when I had the dream, then I was also sixteen in the dream; time had passed just as it had in reality. And, in the dream, I would realize that it was my waking life – school, home, the works – that had been  a dream, while in reality for however many years had passed since that adventure when I was six, my sister and I had lived as feral children in the lonely dog-ridden woods. I had this second dream for far longer than the dream of being nailed in, recurring well into my teenage years and possibly into my twenties – I don’t recall precisely when it stopped. And it was so vivid that frequently I would wake from it to a deep disorientation about which was reality and which the dream.

All of which is preface to saying: the new movie, “Room,” knocked the frigging stuffing out of me.

“Room” – directed by Lenny Abrahamson (whose previous film, “Frank,” I also really liked; I’m clearly a fan) and based on the novel by Emma Donoghue, (who also wrote the script) – tells the story of the survival, escape and post-escape adjustment to mundane reality of a pair of captives. “Ma” (Brie Larson) and her five-year-old son, “Jack,” (an astonishing Jacob Tremblay) live in a 100-square foot garden shed they both call Room. This is their entire world – and the only world Jack has known. You see, Ma was kidnapped by a stranger (Sean Bridgers) seven years ago, and has been held captive by him in this room ever since. He keeps her alive, bringing her food and providing heat and electricity and other necessities, so that he can continue to rape her on a regular basis. Jack, her son by her rapist and captor, was born in Room. He has never been outside.

For the first half of the film, our world is Jack’s world, and while we are aware of the horror that his mother experiences, the camera doesn’t make much more sense of it than Jack does. As well, by the time we meet this little family, the horror of their situation has settled into routine. Jack’s childhood, though strange, is also strangely idyllic, because he has the rapt attention of his mother. She feeds him and exercises him, reads to him and teaches him to read; she makes snakes out of egg shells to be his companions; and she hides him in the bureau when her captor pays his nighttime calls. Her entire existence is oriented around protecting and nurturing him. He is her only joy, her only care, her only interest in the universe.

Or so Jack thinks. Not long after his fifth birthday, his mother tells him the truth. (And we begin to see, really for the first time, what it has cost Ma to be what she has been for Jack for the past five years.) He learns that his mother has a history; that there is an outside world; and that he has a crucial role to play in the escape that will take them out of Room, and into that world outside. In a sequence that is simultaneously harrowing and exhilarating, Jack – who, remember, is only five years old and not only has never been outside but does not really have a concept of “outside” – carries out his mother’s plan for their escape.

And that’s when the trouble starts. Ma is reunited with her own mother (Joan Allen), father (William H. Macy) and new stepfather (Tom McCamus) – her parents’ marriage did not survive the trauma of their daughter’s kidnapping. But, bereft of the purpose provided by her terrible predicament, she comes face to face with how much she suffered, and lost, and begins to break down, falling into a suicidal depression. Jack has to reckon not only with a confusing and unfamiliar world, the need to read new people and situations, experience vantages and enter spaces whose contours he knows not at all, but with the loss of his anchor of stability, his mother.

The escape forms a structural hinge in the middle of the film, similar to the hinge in the middle of “Captain Phillips” that I described in my review of that film, in that there are effectively two films here. But in this case, the second film is not a reversal of the first (the pursuer now pursued, the aggressor now the apparent victim), but rather a commentary on the first. The first movie is primarily about Jack’s experience of life in Room, though through him we can experience something of what his mother is going through. The second movie is still secondarily about the mother’s experience, which we still get primarily through Jack’s understanding of it – but it’s primarily about Jack’s adjustment as he begins to make sense of the idea of Room as just one place among a world of places, a world in which he is quite suddenly not the center. It’s a testament to Jack’s emotional resourcefulness, and to the calm strength of his grandmother and her husband, that he is able to make the adjustment as well as he does, and say goodbye to Room.

That goodbye is a perfect capsule of the movie, and hence a perfect (perhaps too perfect) ending. Jack asks to be allowed to visit Room one last time, and so they are escorted by the police back to the scene of the crime. The shed, which once encompassed an entire world, now appears almost unfathomably shrunken, to us as well as to Jack. Jack says goodbye, and Ma echoes him. In her voice, it’s a plea – that she, and Jack, will actually be able to say goodbye to this horrible place. But in Jack’s voice, it’s the same goodbye any child gives to his or her first home, to a beloved transitional object, or to the first dear friend or relative who dies.

“Room” doesn’t lean too hard on the obvious exile-from-Eden trope, which is why that trope works so powerfully. What Jack is going through – expulsion from an exclusive zone of maternal concern into a world of complexity and independence – is what every child goes through eventually, though not usually in such a sudden and violent way.

Or maybe that expulsion is getting more violent as it is more delayed. Perhaps there’s something especially resonant about this story in our age of helicopter parenting, when too many kids are so thoroughly supervised that “outside” is unfathomable, and when too many mothers feel trapped by a crushing obligation that is also their entire purpose for being.

In any event, it would make an excellent double feature with “The Babadook.”