The film initially shows the downfall of a famed city, then jumps forward many centuries to introduce "Milo," a somewhat awkward young man whose grandfather was captivated by the enigma of the vanished landmass. A wealthy individual, "Preston Whitmore," brings him along on a risky journey to uncover what really happened—a mission that includes a submarine and a team who clearly have their own motives. The initial forty minutes of this extended story feels very much like something from Jules Verne, mainly consisting of drawn-out introductions of the characters, some humour that borders on silly, and by the time the plot starts to move forward, I was already feeling bored. Michael J. Fox brings a bit of personality to his role as the young man, and James Garner seems to be having fun playing "Rourke," who is obviously not to be trusted, but it's not quite enough to give this animated film any real momentum. The visuals are bright, but noticeably computer-generated; they don’t have much depth or detail, and combined with a fairly standard plot, the movie ends up in an indistinct place within the Disney catalog. It isn't as poor quality as some released a decade prior, however it still feels like mass-produced work that is missing creativity and the distinctive qualities this studio was known for. It’s acceptable enough to watch, but ultimately unremarkable.

Source on TMDB