The Mysteries of Gus, The Ghost-Face Dog

Mysteries is the fifth book in the Gus the Ghost-Face Dog Series. Five cousins and their dogs spend their school vacations at their grandparents' ranch in the Texas Hill Country. They have discovered a secret passage to the past whenever they go to sleep next to the old pioneer ruins. When they find a carved message in an old oak tree from a pioneer friend Ethan met on a previous time travel trip, the kids decide to go back in time to help... where they encounter a very dangerous situation. In another story, Ethan and Cal go on a fishing trip with their grandfather along with his friend and neighbor, Scott, who mysteriously disappears. The final story takes place when the cousins and their parents go on vacation on a cruise ship. The kids discreetly witness a suspicious looking man take a case from the ship 's storage room which calls for an investigation. There is never a dull moment