Brittanee Drexel disappeared a year ago on a spring break trip to Myrtle Beach, South Carolina.
Her mom had forbidden her to go, but the teenager went anyway.
The 17-year-old high school junior pretended to be staying with a girlfriend not far from her home in Rochester, New York. She even spoke with her mom by phone to say she was just hanging out. But all the time she was more than 800 miles away in Myrtle Beach, a popular spring break destination
"She said 'I'll see you tomorrow, I love you,' and that's the last time I talked to her," Drexel tells INSIDE EDITION.
Police gave the Investigation Discovery Channel video of Brittanee, shot in the Bar Harbor Hotel by a young man she met on the beach. He's been cleared of any involvement in her disappearance.
The video shows her hanging out on the balcony, sitting on the bed, and texting with friends.
The following day, Brittanee appeared on surveillance cameras going into another hotel to visit with friends. She left alone, and vanished.
Police say it will be a miracle if they find Brittanee alive.
A cell phone signal received the day after her disappearance was traced to an alligator-infested swamp 35 miles from Myrtle Beach.
But Drexel thinks her daughter is alive.
"What makes you think she's still alive?" INSIDE EDITION's Les Trent asked her.
"I have to hold out hope, she's my daughter. I want to bring her back," she said.
Police have reportedly identified four persons of interest in the case.