Once there, the three embark on a madcap adventure through the African outback in search of a missing professor, his gems, and a way to give the pesky customs officials the slip.

Promising himself to “do” Ghana’s northern outback as often as he can, PaJohn Dadson took off one day and went upcountry to visit Bolgatanga. He dwelt on the outskirts of town, travelling around the ...