“The Gateway of the Monster” is a story featuring Thomas Carnacki, a detective who investigates cases of an occult or supernatural nature. It is one of five tales of Carnacki's ghost-hunting exploits that first appeared serially in The Idler magazine in 1910 and were published together with one more as the collection Carnacki the Ghost-Finder in 1913.
After a good dinner, Mr. Carnacki relates his experiences of ghost finding to his limited circle of four friends whom he has summoned to his home in Chelsea.