From the day his parents named him, Nasa Yuzaki has felt connected to outer space...whether he likes it or not. His efforts to outperform the space program veer off course when an accident introduces him to Tsukasa, a mysterious girl with strange powers. Is she an alien, a moon goddess or something else? Since she insists on marrying him, Nasa will have plenty of chances to find out!

Nasa and Tsukasa are on an overnight trip to a hot springs resort! There's so much for them to do, from touring traditional sites to sampling the local delicacies to--nah, let's face it, Nasa is most excited (and terrified) by that private bath in their room. Time for an inopportune appearance by Tokiko, Tsukasa's mysterious and heretofore unseen guardian. Can things still get hot and steamy between our favorite couple? And whether or not they do, will the artist find an excuse to put some supporting characters in swimsuits? Do you even need to ask?