Dust Bunny

Eight-year-old Aurora lives in New York City with her parents. While lying on the fire escape at night, a firefly draws her attention to her neighbour in unit 5B. Intrigued, she follows him to Chinatown one night and witnesses him kill a dragon – actually an armed gang in a dragon dance puppet.

Aurora warns her parents to avoid stepping on her bedroom floor, as she says this will trigger the appearance of a monster under her bed. They attempt to soothe her while setting aside her concerns, but she remains convinced and says "Goodbye" to them. That night, hiding under her blanket, she hears them being attacked and wakes up alone, finding her parents' bedroom is torn apart.

Aurora tries to hire Resident 5B to kill the monster. He finds it more likely that her parents were mistakenly killed by assassins who were looking for him, and informs his handler Laverne. That evening, two hitmen arrive in Aurora's apartment. 5B kills one following a hand-to-hand battle; the other disappears after shooting at Aurora's unoccupied bed. In the aftermath, Aurora and 5B narrowly avoid questioning from Brenda, the child protection agent assigned to Aurora; she reveals enough for 5B to understand that Aurora's birth parents and three sets of foster parents have all disappeared.

Aurora becomes more deeply immersed in 5B's world. They bring the dismembered body of the assassin he killed to Laverne, who reveals that she hired the two assassins to remove Aurora as a loose end, being a witness to 5B's activity. They also encounter an assassin who has a contract on 5B.

The assassin and his team follow them home and converge on Aurora's apartment. Brenda returns as well, revealing that she is an FBI agent (as 5B suspected). 5B, the hitmen, and the FBI engage in a fierce firefight that ends when the monster – a giant, vicious bunny that emerges from the floor – consumes everyone except Aurora.

In the morning, 5B emerges from the floor, presumably spat out by the monster due to having applied a thumb-sucking deterrent. Laverne arrives and 5B pleads with her to not kill Aurora and to get off the floor, revealing that she is his mother. The monster re-emerges and Laverne stands her ground shooting at it before it consumes her. The monster then moves at 5B but Aurora stands between them and tells the monster, "No."

5B understands that the monster is hers and tells Aurora that she can control it. Together, they leave the city to start a new life together. As they drive between fields of sunflowers, their car's shadow on the road has the form of the monster running with them. A mid-credits scene reveals that Brenda survived by hiding in the ironing cabinet.