Berlin, 1926. After the death of their parents, sisters Leni and Annette only have each other. Desperate to support her younger sister, Leni finds work at a notorious cabaret- the Babylon Circus, a place where reality and fantasy merge.

Leni is happiest hiding in the shadows, until she meets resident pianist, Paul, beginning a tentative love affair that will play out over the next forty years.

But can a love born within the feverish walls of the Babylon Circus ever survive? And can the bond between Leni and Annette - tugged in opposite directions of their own - also endure?