This was my first time in Africa. It looked so good—better than I ever expected. I’d pictured it all wrong: muddy tracks, uncivilized chaos. But stepping off the plane, the air hit differently, shattering every stereotype I’d swallowed from bad movies.

We’d arrived at the airport—I couldn’t pin the stopover exactly, somewhere in Nairobi. Now we were crammed into the international Nairobi Railway, chugging toward Zanzibar.

Dad had taken the wrong route, turning our trip into a ...