Ewalt was last seen at the Agate Bar on Main Street in Rosebud County, Montana at 11:00 p.m. on August 20, 1975. She left a female friend there and said she was going to see her brother, a nightclub musician. She never visited her brother and has never been heard from again. Ewalt left behind her car, purse, clothing, paycheck, and her three sons. She had a trust fund from her grandfather, but has not accessed it or any of her other bank accounts since she went missing. At the time of her disappearance, she was in the process of a divorce and was working at the Century Club in Forsyth, Montana.

Little evidence is available as to Ewalt's fate, but her family believes she met with foul play, as it is uncharacteristic of her to leave without warning. Her case remains unsolved.