White Water Terror — Carolyn Keene

Nancy Drew is on a white water adventure that soon becomes a deadly game of cat and mouse.

When George wins a rafting trip on a wild Montana river, Nancy and Ned agree it's time for a vacation. Bess is persuaded to go because there will be boys in the group. But a sinister telephone warning and two near-fatal "accidents" soon put the vacation on ice and Nancy and her friends on guard.

Then when one raft capsizes and another is sliced to ribbons, it's obvious someone is sabotaging the trip. Everyone is a suspect -- until one of the rafters is killed and another disappears. It's clear that Nancy and her friends are being stalked by a ruthless murderer. But why? If Nancy doesn't find some answers soon, she can kiss her vacation -- and her life -- goodbye.