Dinner for Adele

At the start of the 20th century, Ledvina, the police commissioner in Prague, asks visiting detective Nick Carter from New York for his help in solving the case of a missing dog. But Carter discovers his help is soon needed in more serious matters when botanist Baron von Kratzmar is suspected of using his human-eating plant Adele to commit a string of murders. Ledvina and Carter suspect it is von Kratzmar who has been kidnapping his victims and then playing a certain lullaby to awaken the sleeping Adele in time for her to enjoy them for dinner.