The maw

"Milo Luttrell never expected to step inside the mouth of an ancient cave in rural Tanzania. After all, he's a historian--not an archaeologist. Summoned under the guise of a mysterious life-changing opportunity, Milo suddenly finds himself in the midst of an expedition into the largest underground system in Africa, helmed by a brash billionaire-turned-exploration guru and his elite team of cavers. It's a once-in-a-lifetime chance to finally solve a century-old disappearance of the famed explorer Lord Riley DeWar, an enigmatic figure who both made--and nearly ruined--Milo's fledgling career.…