Josh is on the hunt for the lost tomb of Alexander the Great; he dives Egypt's coast, revealing ruins of Alexander's Royal Quarter; he tunnels under modern Alexandria, but a water pump malfunction puts everything at risk.

Josh chases fortune stolen by loyalists to Britain's crown during the American Revolution. Jumping into two investigations of the infamous Doan Gang, Josh helps dig up a cache of plundered coins. Later, a cave search pinpoints the turncoats' hideout.