Astronaut Nan-young and Musician Jay, who embark on the longest-ever long-distance relationship one that bridges Earth and Mars.

Nan-young, whose astronaut mom failed to return to Earth when things went awry during her Mars probe. Nan-young has always dreamed of exploring space too and longs to go to Mars in hopes of finding a trace of her mom. Her dream comes true when she is selected as one of the astronauts for a Mars probe project. Before she blasts off though, she meets Jay, a musician who also fixes retro sound instruments.