Danger in the Endless Cave(1988)
(A book in the Green Street Mystery series)
A novel by Marion Dane Bauer and Dana Brenford
While learning the rugged sport of spelunking on a visit to King Cave, Peter, Kim, and Jason face an even bigger challenge when they find a mysterious trail of cartridges in a deep underground tunnel.
Used availability for Marion Dane Bauer's Danger in the Endless Cave
October 1988 : USA Library Binding