The basic plot involves a young divorcee who buys a money pit of a house with the hope that she can convert it into a hotel. The house is owned by an eccentric scientist [Karloff] and his equally eccentric staff. Dead bodies pile up throughout the film but the laughs do not.
This one can even be skipped by Karloff fans! It's less than spectacular. It just provedsthe point that comedy is a tricky thing to pull off well. It' not a horrible movie, it's just not as funny as it thinks it is. Check out the other films I mentioned instead.
For more info check out the film's entry in IMDB.