Well, just about anything, but all is not lost. The film is full of Browning's atmospheric touches—which made Dracula so creepy—and he does himself better here with extensive fog effects, a "real" flying vampire, and a hot she-vampire that's creepier than Lugosi, himself.
A remake of Browning's London After Midnight (a Lon Chaney silent film classic considered lost), this version is re-set in Prague. Plans for the wedding of Irena Borotyn (Elizabeth Allan) and Fedor Vincenti (Henry Wadsworth) are dampened when her father, Sir Karell Borotin (Holmes Herbert) is found murdered, two holes in his neck and his body drained of blood. The police are baffled, but not the townspeople, who blame it all on Count Mora and his daughter Luna (Bela Lugosi and Carol Borland), who the locals think reside in the Borotyn castle near town, despite being dead for many, many years.
The marriage is postponed, the case, being investigated by Inspector Neumann (Lionel Atwell), goes cold and Irena goes to live with her guardian, the Baron Otto van Zinden (Jean Hersholt). And, wouldn't you know it? Right before the wedding can occur again, another attack occurs—this time Fedor turns up double punctured after walking by the Borotyn castle. Then, Irena is attacked. Things are getting to be a real pain in the neck, so the inspector brings in noted vampire specialist Professor Zellen (Lionel Barrymore), who suggests a two pronged attack (naturally), they'll dig up the body of Sir Karell to see if he in thrall to the vampire, and they'll search the Borotyn castle for Mora and Luna.
There's more to this than meets the eye, and far less with a twist ending that makes horror fans see red.
Still, before they stake these vampires, Browning's atmospherics are fun, effective and slightly risible and although it disappoints for toying with the audience (and for the many 20/20 hindsight "but if..." questions after), it's genuinely creepy.