Captain Blueduck, the notorious pirate, and his legendary lost treasure set the stage for mystery on the island of Jolo in the Philippine Islands. Miss Mallard and Willard seek refuge from a storm in a great banyan tree and become embroiled in a case involving the ghost of Captain Blueduck. It does not take long for Miss Mallard to realize the ghost is a fake, but then who is trying to scare a poor family from their home and why? Miss Mallard and Willard learn the surprising truth: the villain is not trying to scare the family away but to force them to stay. And when Miss Mallard finds the lost treasure, that's just what the family gets to do.