All the best, and thanks for the fish!

Hitchhiking around the galaxy, Arthur Dent landed on the planet during a rainstorm. He seems to be in England on Earth, although he saw the destruction of the planet by the Wogons . Arthur was absent for several years, but only a few months passed on Earth. He is driven up by a man named Russell and his sister Fenchurch , nicknamed "Fennie." Russell explains that Fennie began to rave after the worldwide mass hysteria , when people had hallucinations in the form of “big yellow spaceships” (wogon destroyers that “destroyed” the Earth). Arthur became interested in Fenchurch, but they get to his house before he can ask more questions. In his still-standing house, Arthur finds a gift wrap with the words “All the best and thank you,” which he uses for his Babylonian fish . Arthur believes that Fenchurch is somehow connected with him and with the destruction of the Earth. He still has the ability to fly when he lets his thoughts wander.

Arthur puts his life in order and then tries to learn more about Fenchurch. He accidentally finds her when driving in a car. He gets her phone number, but loses it. He accidentally discovers her house when he searches for the cave in which he lived on prehistoric Earth; her apartment is built in the same place. They learn other circumstances connecting them. Fenchurch says that a few minutes before her “hallucinations” she had an insight on how to do everything right, but then she turned off. She could not remember the essence of insight. Noticing that Fenchurch's legs do not touch the ground, Arthur teaches her how to fly. They have sex in the sky over London.

In a conversation with Fenchurch, she learns from Arthur about hitchhiking a galaxy, and Arthur finds out that all the dolphins disappeared soon after hallucinations in the world. He and Fenchurch travel to California with John Watson, a mysterious scientist who claims to be aware of the cause of the dolphins' extinction. He abandoned his original name in favor of Wonder-Sane, because he believes that the rest of the world's population has gone crazy. Watson shows them another bowl with the words “All the best and thanks for the fish” and encourages them to listen. The bowl loudly explains that the dolphins, knowing about the impending destruction of the planet, left Earth, having gone into an alternative dimension. Before leaving, they created a new Earth and transferred everything from the original Earth to a new one. After the meeting, Fenchurch tells Arthur that while he lost and found something, she found and lost something. She wants them to go together into space and reach the place where the last message of God to His creation is written.

Ford Prefect discovers that the record of the Galactic Guidebook on the Earth consists of volumes of text that he originally wrote, instead of the previous truncated record, "Mostly harmless." Curious, Ford hitchhikes through the galaxy to get to Earth. In the end, he uses a giant robot ship to land in central London, causing panic. In chaos, Ford reunites with Arthur and Fenchurch, and they control a robot ship. Arthur brings Fenchurch to the planet, where the last Message of God to His creation is written, where they discover Marvin . Due to previous events, Marvin is now about 37 times older than the known age of the universe and barely functioning. With the help of Arthur and Fenchurch, Marvin reads the Message (“We apologize for the inconvenience”), utters the last words “I think ... I like it” and happily dies.

• Information in the Science Fiction Lab