As a baby, Kamogawa Asumi's mother suffered a severe injury from a rocket crash. Five years later, after being in a coma since the accident, Asumi's mother passes away, leaving the young girl to grapple with the loss of a distant maternal figure. Amidst her grief, she encounters 'Lion-san', an enigmatic individual donning a lion mask who claims to be a ghost. With Lion-san's guidance, Asumi lays her mother to rest, leading her to a pivotal realization: 'I want to become a rocket pilot when I grow up'.