Plot summary
Something Upstairs is about a twelve-year-old boy, Kenny Huldorf, who tells a story to Avi who had visited the school on a book tour. He moves from Los Angeles to Providence, Rhode Island. He lives in a house of past events, built in 1789. Kenny's room is in the attic. One night Kenny wakes to a scraping noise in the old slave room. When he looks inside, he sees a ghost that tries to get out from a stain on the floor. It moves a box full of books out of the way. Once it is out, the ghost feels the attic walls, in search of something. Kenny and the ghost see each other; the ghost does not speak, and flinches away and disappears when Kenny raises a shoe in defense.
Kenny tells his father there is something upstairs, but his father interprets that as a metaphor for “something you don’t want anyone to know about. Secrets.” Kenny visits the local library, where he meets an old historian, Pardon Willinghast, who is also curious about the property. Kenny tries to talk with the ghost boy, who mutters the word “slave.” He asks Willinghast if any former owners had slaves, but he doesn't get a candid answer. After getting a sample of the floor analyzed by a chemist, Kenny talks with the slave boy, whose name is Caleb, who affirms that's his blood, and that he was murdered in his sleep. He wants Kenny to help him find who did it. Kenny doesn't think that's possible, but as he leaves, he finds his room changed.
Kenny finds himself in an earlier time period. He follows a man who was staring at his window. Another man sees Kenny and asks him to pass a message, which he does, but he also reads it, noting it concerns a meeting aboard The Gaspee. Kenny runs back to his house and returns to his own time.
Kenny asks Caleb why he can't leave. Caleb says his death was unnatural, so he's a memory fixed in time and space. Caleb affirms the men were slave traders, and gives Kenny the approximate day he was killed. Kenny confirms in the news articles that Caleb was found dead in the locked attic room in an apparent suicide.
Caleb denies the suicide, but Kenny agrees to help him. They go back in time and listen in on the conversation aboard The Gaspee, which also includes Pardon Willinghast! The men talk about how they can preserve their slave trade, by motivating the slave trade workers outside to go to Olney Lane to silence the blacks who live there. Caleb disappears. Kenny tries to leave but is stopped by Willinghast, who tells Kenny that he is a memory as well, and that Caleb's running and the men leaving are all going according to plan. He takes Kenny's keychain and states that Kenny could be stuck in this time period forever as a ghost because of altered events.
Kenny goes to Olney Lane and finds Caleb who has a musket. Then the angry drunken mob approaches, but Caleb confronts them, and gets hit in the face with a rock before Kenny pulls him back. The mob sets fire to one of the nearby houses. Caleb is so furious that he shoots and kills one of the mob. The mob tries to go after Caleb and Kenny, but they escape in the rain.
Kenny and Caleb retreat to their house. After figuring a way to lock the room from the inside, Kenny goes out to seek help, but is stopped by Pardon Willinghast, who has a proposal for Kenny. In order to return to the present time, Kenny will have to kill Caleb in the room, and then lock it from the inside to fulfill the suicide scenario. Willinghast also reveals that he originally killed Caleb, and that others were given a similar situation and had killed Caleb. He gives Kenny a double-barreled pistol.
Kenny returns to Caleb and says that he was the murderer, but it was Willinghast who blackmailed him. The boys think of a way to change the situation. They fake Caleb's death using the blood from his cheek, and lure Willinghast into the room. Willinghast arrives and checks Caleb's body but finds he is still alive. He orders Kenny to shoot Caleb and dangles the keychain. Kenny shoots.
Kenny wakes up in the present time and sees there is no stain on the floor. The library article now reads that Willinghast committed suicide and the slave boy is missing. Kenny wonders if Caleb is truly free or whether he is stuck in another house as a memory.
