A defendant may plead not guilty, guilty or guilty but mentally ill. The court may refuse to accept a plea of guilty or guilty but mentally ill, and shall not accept the plea without first determining that the plea is made voluntarily with understanding of the nature of the charge. If a defendant refuses to plead or if the court refuses to accept a plea of guilty or guilty but mentally ill or if a defendant corporation fails to appear, the court shall enter a plea of not guilty.
Ky. R. Crim. P. RCr 8.08