In this mystery, a 13-year old girl gets a crush on her good looking neighbor and soon finds herself entangled in a murder case when a prostitute is found dead in their apartment building. To create an alibi for himself, the handsome neighbor begins encouraging the girl's infatuation with him. In the end, the girl changes her mind about the neighbor and tells all to the police. Unfortunately, they, thinking she is acting out of spite, disbelieve her. A kindly inspector suggests that the girl's mother send her to a convent for protection. He then changes his mind and decides to look into the case; he soon discovers that the girl told the truth. The neighbor is arrested just before he marries an heiress.