This paper considers how the short story “El hombre que siempre soñó” (2002) by Cristina Rivera Garza is built around three discursive axes. The first axis refers to a “realistic” narrative, following a chronological development of the history. The second one is articulated according to the dream as an interruption of the conventional flow of time, and through the incursion of the “revealing moment” (Zambrano, 1986). Between those two axes, we can find a third one, which is made in the latent construction of the mythical isotopy related to the ancient Mexican mermaid in the myths of the origins. The mythical image works then as an “interpreter” (Herrero, 2006) of “reality” and its hermetic background, and it configures as origin and motor of the dream.