Noah is an eighteen-year-old high school graduate and part-time worker who would rather avoid responsibility than face another shift. On a morning when he once again skips out on his job, the doorbell rings. The voice on the other side introduces itself with a simple question: I am an alien. Are you free today?

Reluctant to work and drawn by the alien's gesture, Noah decides on impulse to leave Earth behind. He boards a spacecraft called the Ark, where he begins an unusual shared life with the alien who invited him, a being named Keberinchom. This marks the start of a carefree existence in space, one built on rejecting the pressures of growing up and holding down a regular job.

The story follows Noah and Keberinchom through their whimsical daily routines aboard the Ark. What might seem like an exciting, extraordinary adventure instead settles into a relaxed and leisurely pace, with the two inhabitants treating their cosmic home as a place of comfort rather than discovery. Other beings from various planets are also recruited by the mysterious guide who first summoned Noah, and their presence adds to the unconventional household.

The central narrative arc revolves around Noah's reluctant journey toward maturity, though he resists it every step of the way. His cohabitation with Keberinchom, who is equally disinclined toward adult concerns, creates a series of comedic and gently heartfelt situations. Underlying their laid-back existence is a quieter mystery: what is the true purpose of the guide who recruits beings from across the galaxy and offers them this peaceful refuge? The manga presents itself as a lighthearted science fiction comedy, depicting a universe where every day feels like a perfect day for space living.