Hilde Fursten and Tony Osgood work at the San Diego Zoo. When a new baby monkey is found missing, Hilde Fursten is blamed by Dr. Walther Braun, a visiting dentist. Boris Zelbowski also works at the zoo and is dating Frieda Crawson, Dr. Braun's nurse. That evening, Dr. Braun arrives at the zoo to perform oral surgery on a lion and is found dead in the lion's cage. Tony Osgood is accused of the murder when a witness sees someone wearing Tony's blue sportcoat near the lion's cage at the time.