Trevor, an insomniac lathe operator, experiences unusual occurrences at work and home. A strange man follows him everywhere, but no one else seems to notice him.

Four prison inmates have been hatching a plan to literally dig out of jail when another prisoner, Claude Gaspard, is moved into their cell. They take a risk and share their plan with the newcomer. Over the course of three days, the prisoners and friends break through the concrete floor using a bed post and begin to make their way through the sewer system -- yet their escape is anything but assured.

In the past few days Rome has been the scene of a singular event: when it rains, the manholes exhale a dense steam whose origin and composition is unknown. No one can imagine that whoever breathes in the mysterious substance will have to deal with what he/she represses, their darkest instincts, their anger. Not even the Morel family.

On a winter day in 1961, 31-year-old Anna Eichmayr crosses the Grosshesseloher bridge in Munich, she suddenly stops in the middle of the bridge, opens a manhole and plunges into the depths. The film traces the young woman's life in flashbacks. It goes back to 1945.