His business is time: H.G. Tannhaus is Winden's clockmaker. In 1953, he has his own workshop in town. Over the next 33 years, Tannhaus tirelessly explores the concept of time, eventually writing a book that lays out the theoretical principles of time travel called "A Journey Through Time."
By 1986, he has turned into a quirky old man. He still has his workshop and is raising his granddaughter Charlotte, though he never tells her anything about her parents.
Visitors from another time
The clockmaker receives a number of curious visitors from other points in time. In 1953, older Claudia Tiedemann brings him a set of blueprints and asks him to build a machine, a time machine. It takes Tannhaus decades to fully understand and complete the device.
In 1953, Ulrich Nielsen also visits the workshop. He brings a copy of Tannhaus' book, which won't be written for many more years. He also leaves behind a strange futuristic device, his smartphone.
In 1986, the Stranger pays Tannhaus several visits. They discuss time travel and the clockmaker repairs his time machine. The Stranger also supplies the radioactive Caesium-137 isotope that is necessary to activate the time machine.