Stefan Walz

Undine is a historian and tour guide at the Berlin City Museum specializing in urban development, while Christoph is an industrial diver. Linked by a love of the water, the two form an intense bond, which can only do so much to help Undine overcome the considerable baggage of her former affair.

Alex Kerner's mother was in a coma while the Berlin wall fell. When she wakes up he must try to keep her from learning what happened (as she was an avid communist supporter) to avoid shocking her which could lead to another heart attack.