This study made used of Extended Conceptual Metaphor Theory proposed by Kovecses (2020) to analyze the activation of the metaphor "HUMAN LIFEIS A DAY" in the song Cát Bụi by Trinh Cong Son. We systematically show that the metaphor follows the four-layered activation from mental spaces, frames/domains to image-schema level. The mental spaces provide rich details and experiences for the composer to conceptualize the scenes and then convey his ideology through the metaphor. The important role of context is once again reaffirmed in facilitating the metaphor which is entrenched in the human long-term memory. Last but not least, we also show the Vietnamese unique cultural aspects in the frames/domains level. All in all, the study confirms the applicability of Extended Conceptual Metaphor Theory.