As the expedition team near the end of their journey across Micronesia, it's a race against time for the extreme deep divers as they continue their search for new species.
As Kate Humble explores the Rock Islands of Palau, Mike DeGruy embarks on a unique training programme. The Newtsuit is an incredible feat of submarine engineering - a bright yellow one-man submersible that Mike has to master before he can venture even deeper into the Pacific abyss.