Medical student Paula Henning wins a place in a summer course at the University of Heidelberg, where her grandfather had been a noted professor. During one of her classes on anatomy, the body of David, a young man whom Paula encountered on her train to Heidelberg, turns up on her dissection table. Paula's instructor, Professor Grombek, humiliates her by daring her to dissect the heart. Paula finds that David's body presents strange cuts, and decides to investigate the mysterious circumstances surrounding his death. When she goes to cut a sample for an independent test, she is amazed to find a triple "A" mark near David's ankle. She is then startled by the school's mortuary attendant, who wants to know if Professor Grombek is aware of her acts.