Carla Martin (Amanda Pays) is leaving an English parochial boarding school for the summer to live with her estranged father at an inn in East Berlin.
Hugh Martin (George Segal), her father, who lives on Central Park West, greets her at the Berlin Airport, surprised at how grown she looks.
Hugh has Frau Hoffman humor her and show her that there is merely a broom closet next door, though that room is not deep enough to convince her.
Carla sees flashes of another girl in the wardrobe mirror, starts tapping the wall behind it and gets taps back, and tearing away at the wallpaper, she opens the wall to find a disused cold room, for the hotel was once a butcher's shop and home, and a Jewish dissident named Erich (Anthony Higgins) hiding inside.
Christa is the daughter of butcher Wilhelm Bruckner (Warren Clarke), a member of the Nazi Party who calls her a "little slut" and rapes her in the night.
Hugh is concerned that Carla may be going insane like her mother did and finally makes good on his insistence at having her seen by a doctor (George Pravda).
When they return, Moltke (Clifford Rose), who had previously interrogated her about a visit to a Jewish man referred to her by Erich (something Carla was not able to accomplish in her own experience), is waiting in her bedroom.
The planks Herr Bruckner had sealed it up with are removed, and Carla investigates it, filled with rats as she initially suspected, discovering the place where Christa and Erich's names are carved into the wall.