Police searching for an East Sussex teenager thought to be in France with a teacher from her school say the pair failed to use their return tickets.
Megan Stammers, 15, from Eastbourne, is believed to be with Bishop Bell C of E School teacher Jeremy Forrest, 30.
Police said a friend received a message saying Megan had arrived in France, but return ferry tickets for Sunday night were not used.
The school said concerns had been raised before their disappearance.
Appealing to her daughter at a news conference, Megan's mother Danielle Wilson said: "Sweetheart, I don't care what you've done or why, I just want you home."
Ms Wilson said Megan was "really happy, jumping around" before she disappeared.
'Out of character'
"She said to me, 'Mum can you look me in the eye?'. I looked her in the eye and she said, 'I love you'."
She added that Megan's disappearance was completely out of character.
"She is always in at 7pm, she is not one of these kids to roam the streets, she doesn't go out drinking or anything like that," she said as she made her appeal with Megan's stepfather, Martin Stammers.
Megan was reported missing at about midday on Friday after she failed to turn up for school.
She is believed to have boarded a ferry from Dover to Calais with Mr Forrest, from Ringmer, East Sussex, in his black Ford Fiesta at some point after 21:30 BST on Thursday.
Bishop Bell head teacher Terry Boatwright said concerns had been raised about Megan and Mr Forrest.
"The school, in conjunction with the local authority, Megan's parents and the police, had been addressing and investigating those concerns, in line with procedure, when this happened," he said.
"That investigation will continue and we will decide what action to take."
'Not in trouble'
Several appeals for Megan's return have been posted on Twitter and Facebook and Mr Stammers thanked people for supporting the family.
"Please keep posting, keep tweeting, please keep retweeting," he said.
He said Megan sent him a text message on Tuesday asking to meet him. He arranged to meet her on Saturday but she did not keep the appointment.
Chief Inspector Jason Tingley said the message sent to Megan's friend did not come from her own phone, but police believed it was from her.
"That gives us some comfort that she has arrived safely and she is in France," he said. "That's our last contact."
Police checked the return ferry Megan and Mr Forrest were booked on late on Sunday night, but they were not on it.
Mr Tingley said it was believed Megan had gone to France willingly.
"We need to hear that you are OK," he said. "Your family and friends are extremely worried, but you are not in any trouble.
"My message to Mr Forrest is that this may not have gone as you expected it to.
"Right now our priority is to know that Megan is safe and I would ask you to do the right thing and make contact with us.
"We will work with you to get you both safely back into the country."
Mr Tingley appealed for any members of the public who saw the couple or Mr Forrest's car, registration number GJ08 RJO, to contact French or British police.