Jonathan joins Charlie Donilon on his shark charter boat in Rhode Island, Massachusetts, and learns about how shark tagging has shed light on the biology of and behavior of Blue sharks. Tagging has shown that these incredible swimmers actually migrate completely across the Atlantic ocean. Jonathan tries his hand at tagging a shark and then swims with Blue sharks. We also learn that Blue sharks are not nearly as vicious as they have been reputed to be, and the divers are actually able to pet the sharks! The most exciting moment comes when a shark accidentally gets into the cage, and Jonathan must figure out how to rescue it without getting bitten. Underwater Cavern In a quiet forest in central Florida, a mysterious pond filled with warm clear water hides a secret at the bottom. Jonathan explores the pond to find a spring which leads into a cave. As Jonathan travels underground, he meets unexpected marine life in the dark depths and learns how water travels through an aquifer from the underground world to the surface. Giants of the Depths The Sperm whale holds many records. It is the deepest-diving whale on Earth, the largest toothed whale on Earth and has the largest brain on the planet too. On top of that, it has a reputation for being a vicious beast, thanks in part to Herman Melville's Moby Dick. But the real Sperm whale is a lot different than people think. It has a highly-evolved social life, operates at depths where nobody can see them most of the time, and uses sonar which is so sophisticated that it makes the Navy's electronics look like toys. Sperm whales are very hard to find and even harder to film. In the Caribbean, Jonathan repeatedly attempts to get close to the elusive whales, until finally he succeeds and has an incredible experience eye to eye with a giant who investigates him with powerful sonar clicks.

Perhaps best known for its role as the antagonist in the film Jaws, the Great White shark is probably the world's most feared animal, and easily the most fearsome of the sharks. Jonathan travels to Mexico to meet a Great White up close and personal. Nothing can prepare him for the sheer size and strength of a fully grown Great White shark! He learns how white sharks are being studied and how they react to both people and sea lions. The Bandana Game In the open ocean around the Bahamas, pods of wild Spotted Dolphins frolic in the sunshine. Sometimes, they get bored and approach boats. Jonathan joins dolphin expert Wayne Scott Smith to learn how dolphins interact with each other. Jonathan gets a lesson on how to play the Bandana Game, a game of "keep away" that the dolphins invented and like to play with Scott. The Shark and the Whale In the warm and blue waters off Hawaii, Oceanic White Tip sharks often follow behind pods of Pilot whales. For the longest time, biologists have had no idea what is going on. Are they eating the whales? Are they stealing food from the whales? In an expedition to follow the sharks and observe them, Jonathan finally figured out what is going on, and you won't believe the disgusting truth!

A Sharkwreck mystery Thirty miles off the coast of North Carolina there is a shipwreck on the bottom, 130 feet down. Swarming around the wreck are dozens of Sand Tiger sharks. They look menacing, but they seem to be very docile. What are they all doing there, in one spot? That's what Jonathan wants to find out. Using a variety of filming techniques, Jonathan attempts to discover the secrets of the Sand Tiger shark gatherings at the wrecks, and does the first ever night dive with these sharks...talk about scary! Swimming with Sea Cows When manatees were first seen by Columbus, he thought they were mermaids...but he had been at sea for a long time! Today these gentle marine mammals are threatened by loss of habitat and collisions with boats. This segment explores the endangered manatees of Florida and their struggle to survive, as well as some of the people who are working to save them. The Shark with the Long Tail The Thresher shark may very well be the strangest looking shark in the world, with a tail almost as long as its body. This shark is very rare, almost never seen by divers....until now. Using advanced diving technology, Jonathan visits a remote reef in the Philippines where Thresher sharks show up every morning to be cleaned by small fish.

Wilma the whale What happens when a Beluga whale, normally found far north in the arctic, suddenly shows up in a Bay in Nova Scotia? What happens when she starts swimming with people and approaching boats full of tourists? This segment shows how one incredible friendly whale transformed a town, and captured the hearts of children and adults alike. The Prinz Eugen Once the pride of the German Navy, this 700 foot long heavy cruiser was used by the U.S. as a test target for not one but two atom bombs at Bikini atoll. Today, at the bottom of the ocean, the radiation levels of the Prinz Eugen are low enough for safe exploration. Jonathan joins historian Mark Miller on a trip to explore this mysterious shipwreck. What they find about the condition of this wreck is surprising. The Mysterious Hammerhead Of all the animals in the oceans, the hammerhead shark may be one of the strangest looking. The exact purpose of the wide, flat head is a mystery, but several theories abound. We travel to the shark-infested waters of the Galapagos in Ecuador to learn about the unusual habits of these sinister-looking sharks. Jonathan swims in schools of hundreds of hammerheads, and yet the sharks ignore him. What are the sharks up to?

The Airplane Graveyard During World War Two, a fierce battle between American and Japanese forces on Kwajalein atoll left a trail of debris on the deep lagoon floor. This lagoon now has one of the largest collections of well-preserved aircraft in the world. As part of the first ever film crew allowed onto this secret military base, Jonathan explores a B-25, F4-U Corsair and Dauntless dive bomber still sitting on the bottom of the ocean, as if ready to take off. Killer Clams Giant clams are no myth. In New England, people love clam chowder, but in the Pacific, some of the clams are as big as a suitcase! On a trip to Micronesia, Jonathan goes in search of Giant Clams. These clams are so big that people used to think they caught people--and it almost looks like they could. It turns out that the problem is too many people eating the clams. The Shark and the Lamprey In 1998, Jonathan made a remarkable discovery about Basking sharks, the second largest fish on Earth. While diving with Basking sharks in the frigid waters of the Bay of Fundy, Jonathan saw parasitic lampreys on the backs of the sharks. This had never before been documented, so he returned the next year with a shark biologist and a lamprey biologist to attempt to recover living lampreys from the backs of Basking sharks. They didn't think Jonathan could do it. Wait until you see what happens!