The human civilization has taken gigantic steps in the conquest of the space. For 15 years, with the creation of the three-dimensional Tunnel, they can travel to any Galaxy in the universe.“The Gentleman of the Cosmos” is the company that manages the three-dimensional tunnel and dominates organizes the trips. Many companies follow ahead. One of those small companies is YAT (“Yamamoto Anshin Travel”), commanded by Yamamoto, and his beautiful daughter Katsura, her foreign pet lizard Bucky who is the mascot of the company, the robot, Kanabe who navigates and Utchi, the extraterrestrial pilot, and 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, and becomes the YAT mechanic/janitor after an accident that he was responsible for, so he tags along to pay for the damage, as well to find his father. But to find his father will not 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. In addition, Kanea’s mother had a mysterious and conflicting past with Yamamoto.
Goro Hoshiwatari(星渡 ゴロー,Hoshiwatari Gorō?): Protagonist of the series. He works in YAT to clear off damage costs he had inadvertently caused for the company. Like many shounen heroes, Goro is very brave and has an innate sense of righteousness, along with his longstanding goal of searching for his missing father. He's bossed around by Kaoru for the majority of the series, while he has a deep crush on his daughter Katsura.
Katsura Tenjoin(天上院 桂,Tenjōin Katsura?): Kaoru's adopted daughter. She is sweet and affectionate, but she instinctively defends herself with martial arts whenever she feels in danger. She is a cheerful girl all round and it often rubs off on other people, regardless of their mood. She has some unique paranormal abilities that complement her skills in fighting.
Kaoru Yamamoto(ヤマモト カオル,Yamamoto Kaoru?): Director of YAT and captain of the YAT Dove. Considered an old wolf of space, he was a pirate who was feared by all until he retired. He's very ambitious and egoistic, and organizes trips to cheap destinies. Despite his grumpy personality,he has a good heart. He devotes much of his life to his beloved daughter Katsura.
Ucchi(ウッチー,Utchī?): The Pilot of the YAT ship who dreams about having his own ride. Although a sensible person, he is easily depressed. He has the ability to change his appearance or impersonate people, regardless of their gender. He has solved problems for Goro and Katsura, which reflects his good side.
Kanabi(カナビー,Kanabī?): The navigator of the YAT ship. Although the tours rely on his skills, the ship sometimes arrives at unexpected destinations. While clearly a robot, he has displayed various emotions, although much of it in seemingly pointless arguments with Ucchi.
Bukki(ブッキー,Bukkī?): Mascot of the company and apparently Katsura's pet, although many people are scared of its mean appearance.
Daigo Hoshiwatari: He is Goro's father. He invented the 3D tunnel and created the "Daigo System". While working on the prototype of the tunnel, he was absorbed by the gravitational energy which came from the tunnel, leaving him in a different dimension for 15 years, although he is still 30, because in his world the accident occurred only 20 days before.
Haruka Hoshiwatari: She is Goro's mother. She drives a big truck and has a very strong personality. She had raised her only son, Goro, alone since her husband,Daigo, disappeared 15 years before. She has put on weight since then.
Mr And Mrs Toukichi: they are an old couple and they love travelling with YAT, so they appear in nearly all episodes of the first series. They are hoping that something will happen, because it's a tradition in YAT travels.
Captain Rock: He is the leader of the pirates. When he appears, he always sings the same song, with the rest of his crew. He likes heavy metal, but everybody who listen to him tell that he sings ballads, and this makes him depressed. Long ago, he was part of Yamamoto crew and he is still in Yamamoto's old ship, Nevermore. He is a parody of Captain Harlock.
Nanako: She is part of the crew of Captain Rock. She plays electric guitar and is very good at controlling computers on Nevermore. She was also, part of Yamamoto crew in the past. She is a parody of Yuki, in the Captain Harlock 1978's series.
Hachibee: He is part of the crew of Captain Rock. He plays a digital piano. He loves mechanics and is a parody of Yattaran Captain Harlock. Him and Nanako became a couple.
Ann Marigold: President of the "Gentleman of the Cosmos". She was part of Yamamoto's crew 15 years ago. In the accident of the prototype she stole data about it and used them to became rich and powerful. She married Danzu Marigold, who was a mate of Goro's father and had a daughter with him.
Danzu Marigold: He was the husband of Ann Marigold, founder of "the gentleman of the Cosmos", which was a very weak company at the time. He was a mate of Goro's father, Daigo. He died 10 years before the start of the first series, when he was only 34 years old.
Kanea Marigold: She is the daughter of Danzu and Ann Marigold. She is hyperactive, rich, bad-tempered. She is in love with Goro, although he is not interested on her. She leaders her own ship, which resembles an enormous cruiser.
Daniel: He is responsible of taking care of Kanea Marigold, because her mother is always working and does not have much time to spend with her.
MAM: It is the most important computer in Kanea's ship. It had feelings, because it was designed to take care of Kanea. It has substituted Ann Marigold's role.
6 months have passed since the 50 episode. YAT ships and crew are transported to a very far universe. Soon, they 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". Then, the professor is kidnapped by Emperor Ganon, who wants to use the device to rule the universe. The aim of the YAT crew is finding the kidnapped professor and come back to Earth.
On March 29, 1997, there was an incident involving the episode "The Mysterious Father" (まぼろしのオヤジ,Maboroshi No Oyaji?) in which four children were taken to hospitals by ambulance after reportedly watching a scene in the episode with rapidly flashing red and white colors. Later broadcasts of this episode were edited so that the flashes were not so fast, unlike the infamous "Electric Soldier Porygon" episode of Pokemon, which was completely banned. Similar incidents were also reported following the "Pokémon Shock" incident.