Who and why brutally killed a promising girl, and even right after the party she threw? Many are absolutely sure: the killer is her boyfriend, jealous, domineering, and has big problems with self-control. But he screams at the top of his voice about his innocence, and the evidence of his guilt is not obvious. An accidental witness to the crime can help find the culprit. However, this witness is unusual: he tells the absolute truth, because he does not know how to lie, but he speaks in such a way that it is extremely difficult to establish an accurate picture...