Blanton (D) filed a complaint against King (P) claiming P ran a red light and struck D's vehicle. D alleged that P was negligent and that negligence 'was the sole, direct and proximate cause of the accident, injuries, and damages suffered by D and her motor vehicle. 'Blanton (D) agreed to voluntarily dismiss her claims with prejudice in exchange for a cash settlement. P did not file any counterclaim in response to D's complaint. P filed the present action and alleged that it was D who ran a red light and caused the 23 April 2010 collision, and that D's negligence was the sole proximate cause of injury to P. D filed a motion to dismiss alleging that P's action should have been filed as a compulsory counterclaim to D's 14 July 2010 action. The trial court agreed with D and dismissed P’s complaint. P appealed.