"Down in the Dim Kingdoms" by Tobias Buckell
An adventurer carried back spoils from a journey to the center of the earth. Now, his family joins him on a return trip, hoping to ensure their access to his fortune. This story appears in the anthology LOST WORLDS AND MYTHOLOGICAL KINGDOMS, available now in hardback, e-book and audio. Tobias Buckell's collection SHOGGOTHS IN TRAFFIC AND OTHER STORIES is available in paperback, e-book and audio. Content advisory: Violence, death