While the main characters are Melanie, April, and Marshall, the setting for this story is clearly under the domain of the Professor.
It is the storage yard of his proprietorship that the children steal away to, in order to play their secret game. His unused goods prove to be a veritable smorgasbord of accessories for them to put to use.
As mayhem rears its head in the form of murder, the children's activities are curtailed. It is not the first one that year. The Professor, being a recluse of sorts, becomes a suspect. This idea is bolstered by the police seen at the old man's store.
Children cannot be contained forever, and their secret game resumes. They return to the storage yard. One night April is alone, in the storage yard, with the Professor watching from his store window. Unfortunately, serial killers can also not be easily contained. The murderer attacks the young girl.
Being a protector, not a pervert, the Professor intercedes and summons help.