Hannah Kobayashi was supposed to continue to New York after just a brief layover at Los Angeles International Airport.
But she apparently missed that connecting flight. Her family says the last they heard from her was in a few cryptic text messages in which she said someone was trying to steal her identity.
Hannah's father Ryan Kobayashi has flown to Los Angeles to help search for her.
"She's been to Europe, Japan, but it's just never happened where she's not in touch with anybody," he told Eyewitness News.
He says after Hannah missed her flight to New York last Friday night she started sending odd texts to family members mentioning a "spiritual awakening," apologizing about craziness and then texting: "was definitely intercepted."
Even more frightening - Hannah texted another friend that someone may be trying to steal her money and identity.
"She felt like she was in danger," her father said. "She felt like somebody was trying to get her identity or her phone."
Hannah's aunt, Larie Pidgeon, says this behavior is unlike her niece, who had made plans to attend an event in New York.
"She's very responsible. She was looking forward to this event so much. She had a hotel room booked that was a couple of thousand dollars, the ticket for the event was a couple of hundred dollars."
Some clues to her possible whereabouts have come from social media sleuths. A photo was posted to Hannah's Instagram account over the weekend. Some social media followers of Hannah's aunt were able to deduce that the photo was taken at an event held at The Grove. More detective work uncovered a video on YouTube that appeared to show Hannah.
Her phone last pinged at LAX but is now dead.
Family members say they've filed missing person reports with both LAPD and the LAX Police Department and are themselves starting their own search for Hannah.
"We're just hoping that she is safe and healthy and alive," her father said. "And if anybody knows anything we'd just really appreciate any kind of help."