Brie Larson is trapped in a tiny room below ground — until she’s not — in the first teaser trailer for the upcoming adaptation of Emma Donoghue’s bestselling novel, Room.

The film follows a 5-year-old boy, Jack (The Smurfs 2’s Jacob Tremblay), who is held captive along with his mother (Larson). The teaser, released Thursday, shows them doing typical mother-son activities — playing, singing — and then, unsettlingly, screaming for help as nobody seems to hear. She’s also heard coaching her little boy though a plan in hopes they can escape to the outside world.

Room, directed by Lenny Abrahamson and also starring Joan Allen, Sean Bridgers and William H. Macy, will screen at the Toronto International Film Festival in September, before opening in New York and Los Angeles on Oct. 16 and nationwide on Nov. 6.