Sir Borotyn, a prominent Prague resident, is discovered murdered in his home, with all indications pointing to a vampire assault. The victim's friend, Baron Otto, and the physician who analyzes the body are certain that the vampire is the mysterious Count Mora, or perhaps his daughter, but receive little help from the law. Professor Zelen, an expert in the occult, is called in to assist with the investigation.
Wrongfully convicted of a robbery and murder, Paul Lavond breaks out of prison with a genius scientist who has devised a way to shrink humans. When the scientist dies during the escape, Lavond heads for his lab, using the shrinking technology to get even with those who framed him and vindicate himself in both the public eye and the eyes of his daughter, Lorraine. When an accident leaves a crazed assistant dead, however, Lavond must again make an escape.
Poor physics student Marie is studying at the Sorbonne in 1890s Paris. One of the few women studying in her field, Marie encounters skepticism concerning her abilities, but is eventually offered a research placement in Pierre Curie's lab. The scientists soon fall in love and embark on a shared quest to extract, from a particular type of rock, a new chemical element they have named radium. However, their research puts them on the brink of professional failure.
