>> reporter: in the wee small hours of the morning, while the whole wide world is fast asleep, mary bennett is awake. not because she wants to be, but because some things stay with you, whether you want them to or not. and for mary bennett, it's the time -- 3:40 a.m. >> every day i wake up around that time. it's embedded in my brain. >> reporter: for more than two decades, that particular time has stabbed her in the heart, pulled her awake. it's an internal clock, permanently set to the worst day of her life. it began with a phone call, then a knock on the door, and news of something that should never have happened to this family, to this girl. >> when she would come inside the house, her favorite thing was, "i'm home. what's for dinner?" even if somebody -- we just finished cleaning the kitchen, she'd still ask, "what's for dinner?" that was cathy. >> reporter: cathy torrez grew up in placentia -- a small town nestled amongst the sprawling cities of southern california.