Heinrich Gustav Tannhaus is a clockmaker who operates a shop in Winden, and the adoptive grandfather of Charlotte Doppler (real grandfather of Charlotte Tannhaus). He is the author of A Journey Through Time, a book which discusses black holes, spacetime, and similar subjects, and has appeared in educational videos teaching about the same.
He provides many voiceovers, and is first seen on TV in the bunker in "Lies." He is not established as resident in Winden, however, until the Stranger visits his shop in "Past and Present." The Stranger returns several times over the next few days to discuss time travel, determinism, the 33-year cycle, and related matters. It is later revealed that these conversations took place in 1986, that Charlotte is not his biological granddaughter, and that the Stranger had come to visit to have Tannhaus repair his damaged apparatus. Tannhaus admits as well that he does not fully understand all the concepts in his own book, and is only a pawn in a larger war.
In Season 3, Tannhaus is revealed to have created both Adam's world and Eva's world in an accident taking place in the Original World.
Nothing is known of Tannhaus's childhood or family background, but in 1953 he is operating a modest clockmaker's shop in town. He counts among his patrons Daniel Kahnwald, then chief of the Winden Police, who once sent his daughter Ines to the shop to retrieve his watch, where she encountered a bemused Ulrich Nielsen from 2019. A mysterious older woman approaches him later with a set of blueprints, asking him to build a clockwork apparatus based on those plans.
In 1986, Tannhaus is still working in the same shop, although white-haired and bearded. He is raising the teenage Charlotte, although how he assumed custody of her is unclear. With this appearance he also appears on a video being shown in the bunker about wormholes, and on the back cover of A Journey Through Time. The Stranger, after a number of conversations, asks him to repair his apparatus. Tannhaus says doing so is beyond his abilities, but later retrieves a nearly identical unit—the one he had attempted to build from the blueprints—from a shelf.
When the Stranger returns to retrieve the device, Tannhaus explains that he has not. He has, however, used it to understand how to complete the one he had begun in 1953. He uses the cell phone Ulrich left behind in 1953 to trigger the device, and an empty chamber turns out to be a slot for Cs-137, which the Stranger produces. Thus, not only was the past influencing the future, but the future was influencing the past.
By 2020 Tannhaus is said to have died a number of years earlier, and his adoptive granddaughter Charlotte Doppler has inherited the shop. As Tannhaus is the only family she ever knew, however, she has chosen to hold on to the space and all its contents.
The name H.G. Tannhaus is an allusion to author H.G. Wells, who wrote the science fiction novella "The Time Machine," which popularized the concept of purposeful time travel and coined the term "time machine."
Tann is a poetic word referring to a forest of fir trees, thus Tannhaus one who makes his home in the forest. It may also allude to the legend of Tannhäuser, made famous by the Richard Wagner opera, who becomes a willing captive of Venus, and is later filled with remorse over it, but cannot obtain absolution, and so returns to Venus in the end. The name Tannhaus may also be a reference to Blade Runner's Tannhäuser Gate.
- → See 23 images of H.G. Tannhaus at Images of H.G. Tannhaus.