The series is set in the year 5808; human civilization has taken gigantic steps in the conquest of the space, and with the creation of the three-dimensional tunnel, people can travel to any Galaxy in the universe.

The main characters of the series are part of Yamamoto Anshin Travel (YAT), with the plot revolving around Goro Hoshiwatari, an adolescent who has left his home to travel by the space and to find the whereabouts of his father, who disappeared fifteen years ago during the explosion of the main transporting center of the three-dimensional Tunnel that he created.

Goro falls in love with Katsura, the commander's daughter; and becomes the YAT mechanic/janitor after an accident that he was responsible for, so he tags along to pay for the damage and to find his father as well.

Finding his father turns out not to be his only problem, since Kanea, a young lady whose mother is the owner of "the Gentleman of the Cosmos", is in love with him.

They soon discover that the person responsible is Professor Nota, a scientific who is working on a teletransportation device, helped by a cat-like girl with psychic powers called "Pinky".