Transcript for Student Disappears on Way Back to University of Montana
He sure is. So many questions. The all-out search for a college student who disappeared. Lucius Robbi hasn't been seen in a week and we have more. Reporter: Friends, family and volunteers are desperately searching this vast mountain wilderness for any sign of 21-year-old Lucius Robbi. We're very, very worried at this point. Reporter: It's been one week since Robbi set out from horseshoe bendeading for missoula, Montana, to start his junior year in college but never showed up. It was his first day in school and he's not the kind of boy that would miss that. Reporter: His family says he is a skilled outdoorsman would worked summer as a rafting guide. They say he planned to explore along the way, even bringing along two Orange kayaks. The plan was drive halfway, camp someplace, maybe do a day hike, he's an avid kayaker. Reporter:over night a new clue. Volunteers scouring through gas station surveillance footage spotting what appears to be Robbi's car in garden valley, Idaho, just 30 miles from where he started. About 20 minutes later his family says his cell phone was picked up near the town of loehmann but from there the trail goes cold. I am desperate to find him and desperate to know that he's all right. Reporter: Now his family and an army of 100 volunteers are pouring over maps calling for more planes and helicopters hoping they spot those bright Orange kayaks that lead them to Robbi. If anyone can survive out there for seven days, he can do it. Reporter: For "Good morning America," Clayton Sandell, ABC news, Denver.
This transcript has been automatically generated and may not be 100% accurate.