"The Lumber Room," like Saki's "Open Window" is a little more lighthearted than his darker tales such as "The Interlopers." At first glance, "The Lumber Room" seems to be about a clever boy who outwits his aunt. However, the story does touch on issues such as a boy's desire to explore and to do exactly what his authority figure has told him not to do. Moreover, Saki uses Nicholas, the main character, to warn adults to be careful of using scare tactics, disciplining out of anger, or of lying to children. Nicholas's aunt constantly makes threats, most of which seem only to entice Nicholas to test them; she also disciplines Nicholas out of frustration and anger rather than really trying correct his behavior, and Nicholas catches her in a lie which he readily connects to "The Evil One," leaving his aunt no viable explanation of her own behavior.
Overall, the story's tone is humorous, and Saki does not portray any violent injuries or deaths, but for any adult reading the story, the author is able to stress the importance of being careful what you say to ever-observant children.