The mystery at Bob-White Cave 1st Random House ed.

The Bob-Whites, minus Di and Dan, join Andrew Belden at his cabin in the Ozarks for a holiday. Trixie has them in all involved in an adventure from the moment she decides to hunt for the valuable ghost-fish. She is saved from the attack of a wild cat by a "ghost" and is almost drowned in an attempt to find the rare ghost fish, but their adventures lead them to reveal the identity of the ghost and bring a family back together.