Cast adrift in the Pacific Ocean, nine men set out to recreate one of the greatest survival feats of all time: the 4000-mile journey of Captain Bligh after the legendary mutiny on the Bounty.
Anthony Middleton from SAS: Who Dares Wins steps into Captain Bligh's shoes as the leader of the expedition, joined by eight other men including a carpenter, a doctor and several specialist sailors.
Last week we saw tensions rise as the eight remaining men leave their paradise island to face the most challenging leg of the journey so far: a 1600-mile passage through the treacherous Coral Sea.
But trapped together on a tiny boat, with no wind and with rotting food and a nasty case of cabin fever, tensions were close to breaking point.
In tonight's fourth of five episodes, the remaining crew members face their biggest challenge yet: finding a way through the Great Barrier Reef.
If they get it wrong, this vast wall of coral could rip out the bottom of their tiny wooden boat.
Meanwhile, After two weeks with no sight of land, Restoration Island comes as a welcome relief, until Ant has an accident.
As their adventure continues, the men also have to deal with sharks, crocodiles and giant centipedes, but there's nothing more dangerous than Australia's searing heat.
Mutiny airs tonight at 9PM on Channel 4.
The series concludes next Tuesday night on Channel 4.