>> reporter: rose wrote the postcard to caroline who moved to new york city. >> carol was my best friend. we did everything together. she was my support system. she was like a sister to me. >> reporter: rose's friend caroline followed a boyfriend to new york, only to be left heartbroken. she wrote rose for advice. her reply bu plply was the post hoping to entice her back home. >> you thought she didn't write back? >> that's correct. i thought she made a decision, which was okay with me. i felt, well, caroline knows what's best for her. i never heard from her. >> reporter: where did you think caroline had been all these years? >> i thought she was still in new york. >> reporter: we found caroline. she wasn't in new york. >> hi! >> reporter: nice to meet you. what are you doing here? >> i live here now. >> reporter: here in san diego? >> yes. >> reporter: ten years ago caroline moved back to her home state, always wondering what happened to her friend rose who she thought had never...