To Hell... and Back?
General information
SeriesSea Monsters
Episode number3
Featured creaturesMegalodon
Giant Mosasaurs
Broadcast information
Original airdate23 November 2003
Chronological information
Previous episode
Into the Jaws of Death
Following episode
Water Dwellers

This is the third episode of Sea Monsters and has the last 2 deadliest and starts with the finishing part of the 3rd most deadly place ever! It is called "To Hell..... And Back?". 


Full synopsisEdit

The PlioceneEdit

Nigel has been knocked off the boat by the shark and when he swims back, he finally managed to land a hit with the shark-camera, and the Megalodon grabs and swallows the chum. In a few days, they find the camera floating in the sea, and when they load it into the on-board television, they watch the Megalodon in question attack a Cetotherium (also a whale.)
SM1x3 MegalodonStalksCetotherium

The Megalodon moments before attacking a whale. (Sea Monsters)

When the crew of the Ancient Mariner head backwards in time, Nigel says that as the Ice Age begins, the whales that Megalodon preyed on migrated to colder waters, where Megalodon could not follow. Megalodon is doomed to extinction, by hunger.

The JurassicEdit

This is the second most dangerous sea. Hazards include Liopleurodon  (25/28 m), the largest carnivorous animal of all time. Nigel spies a school of migrating Leedsichthys (25/28 m). One weaker one is lagging behind the school, and a native Metriorhynchus (3 m) and a foreign Hybodus (2 m) shark launch a joint attack. Using sonar, Nigel discovers that a huge Liopleurodon (28 m) is heading toward the injured and dying Leedsichthys (28 m). The camera spots it circling the Leedsichthys which is already dead, though the Liopleurodon is eventually spooked away by the camera.

Nigel equips his and the cameraman's diving suit with a chemical system that will spray a cloud of deterrent at the huge pliosaur should they get too close. The crew use huge waterproof lights when they descend to the corpse of the Leedsichthys, because it is night. A pair of Liopleurodon (each 18 m and 20 m) are feasting on the carcass, and Nigel starts to move closer toward them. When one turns its head towards him, Nigel panics and ejects the chemical, which works on the huge predator. 

The CretaceousEdit

Nigel is now entering his final sea mission in "Hell's Aquarium" as he calls it. On the land there's T. rex  (12 m), but even the most famous land predator of all time can't compare to what's in the water. After viewing a colony of Hesperornis  (2 m) on the coastline, Nigel and another member of the Mariner pause for a second to view a huge underwater bloodbath. As far as Nigel (using a periscope) can figure out, an elderly Hesperornis was killed, and the resulting carnage has attracted many sea animals, such as Squalicorax  (5 m), and Xiphactinus  (6 m). However, Nigel noticed another predator around: a mosasaur known as Halisaurus  (5 m). Nigel and the crew head out to deeper water in search of Tylosaurus  (14 m). But Nigel explains that this sea is far too dangerous to go diving in because of mosasaurs (18 m) and other huge carnivores like Xiphactinus. Instead, the crew of the Ancient Mariner have rigged an ROV to dive for them, while the sonar and cameras on the side of the boat would give them early warning if any mosasaurs are nearby.

The next morning, Nigel discovers that they have hit a dead Archelon  (2 m), which was mauled by some other predator before being hit by the boat. Later, after managing to domesticate a Pteranodon  (6 m), the sonar picks up some creatures right beneath the boat. This was a good time for them to use the ROV, and when they send it down, the crew finds that it's a small pod of Elasmosaurus (12/14 m) riding their wake like 21st century dolphins, but soon they depart due to the risk that they may provoke the herd. Some of them knocked the ROV when they were investigating it, and an Archelon (3 m) is also spotted. Having done the same thing with present-day leatherback turtles, Nigel risks his personal safety to track down the Archelon and ride it. He and the cameraman ride off in the small inflatable raft.
SM1x3 NigelRidingAnArchelon

Nigel Marven riding an Archelon

Before long, Nigel finds the Archelon when it comes up to the surface for air. He dives, grabbing onto the huge turtle's shell. But not long after, the sonar picked up something nearby: a Xiphactinus was circling Nigel and the Archelon. He quickly makes his escape back up to the raft, but disaster strikes. A family pod of Tylosaurus (6/18 m) attack and completely overturn the raft, plunging the crew into the sea. Fortunately for Nigel, the Tylosaurus (18 m) seem more interested in the boat than the humans, and they quickly escape back to the Mariner. However that night, as the men sleep, the tracking device starts going off. It appears to show several kinds of mosasaurs (8/18 m) that appear, apparently attracted to the Mariner, and rush straight to the boat, leaving the crew's fate unknown.
SM1x3 PodOfTylosaurus





Original airdateEdit

  • 23 November 2003 19.00 BBC One


  • 18 December 2003 19.30 BBC Three
  • 1 September 2005 19.00 BBC One
  • 28 October 2005 03.05 BBC One
  • 4 November 2006 20.00 BBC Three

External linksEdit

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