21 Emon, the protagonist known as the Hotel Galaxy Manager, is the 21st-generation heir to a family hotel business tracing back to the Edo period. As the designated successor, he shoulders the responsibility of managing and preserving the family's historic hotel. His daily existence revolves around ensuring smooth operations amidst persistent financial pressures threatening closure, addressing diverse guest needs, and resolving operational issues to maintain service standards.

While dedicated to upholding his family's legacy, 21 Emon harbors a personal dream of becoming a space pilot and exploring the cosmos, creating an internal conflict between his hereditary duty and his interstellar aspirations. In navigating the hotel's challenges and guest incidents, he consistently receives aid from his companions: Gonsuke, a robot, and Monga, a small alien.

The series unfolds in a futuristic era where Earth functions as a tourist hub for space travelers, amplifying the hotel's significance and operational demands. The documented media does not portray significant character development or evolution in his role across adaptations.