Though there's danger afoot in Mystery Island, the film is eminently suitable for the whole family. A group of adventuresome kids come upon a desert island, which they proceed to explore. There they meet a Ben Gunn-style hermit, who turns out to be a retired pirate. Happily, the buccaneer is of the golden-hearted variety. With their new-found friend, the kids thwart a gang of nasty counterfeiters. Mystery Island seems to have been the maiden effort for both director Gene Scott and his very small cast of actors. ~ Hal Erickson, All Movie Guide