King Solomon's Mines & Allan Quatermain/Henry R. Haggard

In King Solomon's Mines, Sir Henry Curtis and Captain Good persuade Allan Quatermain
to help them find Sir Henry's brother George, who has gone missing in the unexplored
African interior while searching for the legendary treasure trove of a lost kingdom.
Quatermain agrees to lead the expedition, though he has little hope they will return
alive. After suffering unimaginable hardships, they find the treasure hidden deep
within a mountain, but while they are admiring the hoard the vast stone door closes.

Their store of food and water rapidly runs out and the trapped men
prepare to die, but in the nick of time they find a way of escape. On their return
trek to civilisation they succeed in the purpose of their expedition when they miraculously
come upon George Curtis, alive and well. In Allan Quatermain, they return to England
with enough of the treasure to live in style, but Quatermain lures them back for
more African adventures.