When Charles Ashton brings home his second wife, he fails to notice the hate and jealousy in his secretary's eyes. He is unaware of the dangers that threaten his wife as his secretary turns the full force of her malice upon her. The shocking truth is that she killed the first wife and intends to lock the new wife in a library vault where she will suffocate within two hours. A delightful old biddy who holds the solution in her hand and who might save the wife does not, unhappily, remain alive either. The key is lent to the young stepson. Will the vault be opened in time?