Daisy Rain goes to her apartment in the Lusman Arms, a former luxury hotel undergoing renovations, and is beaten to death with a hammer by a man wearing a balaclava.

In another room, new tenants Nell and Steven Barrows, a teacher, and a medical intern are introduced to the amenities and a few of the residents by Byron, the building manager.

As days pass, the Lusman Arms are plagued by mysterious circumstance; strange noises are heard throughout it and coming from the intercoms, Nell finds a trinket containing human teeth in a wall, and Julia and another tenant vanish, having been killed (with a drill and a nail gun, respectively) by the ski-masked murderer, who hides their bodies.

Nell returns home and finds a hatch on the roof of the building that allows entrance into the townhouse, where she uncovers a room dedicated to the Golden Age of Hollywood, torture chambers, and dozens of corpses.

A teenage resident discovers that the webcam he had been using to spy on Julia had recorded her death, prompting him to go to Steven, who finds Nell's notes about the building, and goes looking for her along with the boy, Byron, and the doorman.

The Barrows are found by Chas, who tries to lead them to safety, and murmurs that Coffin Baby came into the world when he clawed his way out of his dead and buried mother's womb.

The authorities arrive and take Steven to a hospital, and as Nell returns to her apartment, the police lift up the debris that fell on Coffin Baby, who has disappeared.

The mix of black humour, supernatural mystery and straight up slasher horror never completely mesh and you can’t helping thinking that things would have been better if they’d just stuck to a subgenre.

"[9] Variety wrote, "Toolbox may not renew the splatter genre in any significant way, but the chills and kills prove Hooper, when armed with the right script, can still tighten the fright screws".