Dr. Tokio Taimu, known as Professor Humphrey Bumble in the English dub, is the eccentric inventor and owner of the Flying House. He is an absent-minded and somewhat bumbling scientist, whose well-meaning but often misguided actions drive the plot of the series. His personality is that of the classic eccentric professor, deeply absorbed in his inventions but frequently oblivious to the immediate chaos he causes. This characteristic is reflected in his English name, Bumble, which suggests a clumsy or faltering nature. His Japanese name is a meaningful play on words, as Taimu is the Japanese rendering of the English word time, directly referencing his life's work.

Dr. Taimu's primary motivation is his passion for science and time travel. His greatest creation is the Flying House, a unique vehicle that is half rocket ship and half house, capable of traversing time. The series' central conflict begins because of his direct actions. In an attempt to generate power for his time machine by recreating Benjamin Franklin's famous lightning experiment with a kite during a thunderstorm, his plan backfires spectacularly. Instead of simply powering the machine, the experiment causes his robotic assistant, S.I.R., to go berserk and inadvertently sends the Flying House, along with a group of visiting children, on an uncontrolled journey into the past.

In the story, Dr. Taimu serves as the catalyst for the adventures, though he is rarely the hero who resolves them. His errors in judgment and miscalculations regarding time travel are a recurring obstacle, as the children soon realize that his guidance will not lead them on a quick route back home. He fits the archetype of an adult character who is often unhelpful in a crisis, sometimes making situations more complicated than they need to be. Despite his flaws, he is not a villain but a well-intentioned scientist whose enthusiasm for discovery repeatedly gets the better of him. His key relationships are with the three children—Justin, Angie, and Corky—who become his accidental companions, and with his robot, S.I.R., whom he created. While his abilities as an inventor are remarkable, as evidenced by the functioning time machine and a sophisticated robot, his practical skills and common sense are notably lacking, making him a classic example of an academic who is brilliant in theory but prone to failure in practice.