If you feel like throwing up for a couple hours, take a look at the Wikipedia page for the Elisabeth Fritzl case. Fritzl was imprisoned in 1984 by her father Josef; she didn’t escape until 2008. In the intervening years, Josef repeatedly raped her, and she gave birth to seven of his children; four of them remained incarcerated with Elisabeth, while the other three were adopted by Josef and his wife (he claimed he found them abandoned). Finally, after 24 years of the worst torture imaginable, Elisabeth managed to break free.

Her tragic and horrifying story served as the loose inspiration for novelist Emma Donoghue in the writing of her book Room, which has now been turned into a movie of the same name. The film, directed by Lenny Abrahamson and written by Donoghue, changes the details without diminishing the horror. It’s told primarily from the perspective of a child named Jack (Jacob Tremblay) who’s born in captivity. For seven years his Ma (Brie Larson) has been locked up and abused by a man she calls Old Nick (Sean Bridgers); now five, Jack’s finally beginning to question this peculiar living situation.

Having spent every minute of his life in the tiny cell he calls “Room,” he believes it is the totality of the entire world, with he, Ma, and Old Nick its only “real” residents. (He refers to everything beyond Room’s walls as “outer space.”) For years, Jack accepted this arrangement and took Ma’s assertion that the people he watched on Room’s television were all “imaginary” at face value. But Jack’s expanding consciousness poses new problems for Ma, as does the revelation that Old Nick recently lost his job. Fearing her and her son could be killed, she devises a daring escape plan.

What happens next feels like a spoiler, though the film’s trailer doesn’t hide it; for now, let it simply be said that Ma’s plan is attempted and life for her and Jack changes forever. Even afterwards though, Room remains squarely focused on Larson and Tremblay, who collaborate on an astonishingly convincing portrait of a mother and son. Larson previously played a counselor for troubled teens in Short Term 12; she has an uncanny ability to connect with child actors and to coax great work out of them.

As touching as Larson is in embodying Ma’s struggle for freedom and her boundless love for her son, Tremblay is even better. His voiceover brings us inside Jack’s mind, and his performance during and after the escape attempt, as he reacts to life in “outer space” for the very first time, is incredibly poignant. Tremblay’s Jack is immediately in the conversation for the best performance ever given by a child actor. (The youngest Best Actor nominee in Oscar history is Jackie Cooper, who was 9 years old when he was recognized for 1931’s Skippy. Tremblay is 8 years old now.)

Abrahamson’s last movie was the 2014 dramedy Frank, a dramedy about a brilliant but troubled musician; Room confirms his gift for delicate and sensitive portraits of characters struggling with emotional trauma. Earlier this week, another critic at the Toronto Film Festival described Room as “stifling torture.” He meant that as an insult, but that phrase could also be applied as a compliment to the way Abrahamson makes Ma and Jack’s imprisonment feel so claustrophobically real. If parts of Room weren’t stifling, it wouldn’t be a very good movie about a woman who’s been locked in a cell for seven years, or a very appropriate tribute to the resilience of women like Elisabeth Fritzl.

The same writer also claimed that only a “feminized critic” could truly love this film. If that’s the case, call me a feminized critic — one deeply moved by Room’s message about the bond between mother and son, and the way it brings the best out of people in the worst of situations. See it without tissues at your own risk.