Summary In Antarctica, excitement and anxiety rise as Capt Peter Hammarstedt and the crew of Sea Shepherd's Bob Barker go in dogged pursuit of the notorious poaching vessel, the Thunder, that leads them into a dangerous ice field that can trap and crush a ship in a matter of hours. As the chase heats up, a tense - and potentially dangerous - encounter looms. Eight hundred miles away, a second Sea Shepherd vessel, the Sam Simon captained by Sid Chakravarty struggles to haul up illegal gill nets that are wreaking havoc on all the marine life in the area. In Tanzania, JD, Mike and the team capture an explosives dealer and begin an undercover sting operation that gradually leads them up the chain of command to the so-called "superdealer," for whom they set a trap. Journalist Jim Wickens joins a patrol to crack down on illegal fishing in Palau's national waters, which are a protected shark sanctuary. The enforcement team comes across a Vietnamese boat loaded with shark fins, and must now produce hard evidence to arrest the poachers.

• Documentary