In preparation for his deepest ever dive, Ross returns to training with dive master Neil Brock and explores the site of Britain’s most famous wreck: the Mary Rose.

Ross hops from Portsmouth to Plymouth and explores a coastline littered with treasures. A bout of hypercapnia leaves Ross shaken after the dive of a 17th century shipwreck.

The quest continues in the Red Sea off the coast of Egypt, a deeply personal journey given Ross' grandfather fought in the North African campaign during World War II.