. ♪ >> welcome to "dateline." 23-year-old kristina morris vanished without a trace. th no clues and only blurry individual yog to go on, could the clue investigators needed have been scribbled on a trash post-it note. >> kristina was afraid of the dark. >> through grade school she woke up in the middle of the night. we knew about it because she was in our bed. >> you could hear the feet coming down the hallway. >> she was scared of the boogie man. you know, the boogie man was going to get her one day. >> it was something she never really got over. >> 23 years old, was sleeping with a night light. >> always a bathroom light on. >> yeah. >> and it wasn't just the dark that scared kristina. it was what might happen in the dark. >> kristina had a fear her whole life she would be taken. >> taken, abducted? >> yes. >> where did this come from? >> i don't know, but her absolute worst fierce is exactly what happened to her. how many people actually live their worst nightmare? ♪ >> from early childhood kristina morris's fierce didn't slow her down. >> she's not one to sit in f