ahead. After following the river for two miles he sees something in the distance, but before he can provide more details the server crashes and he loses contact. Jack and the rest of the group press on, thinking the problem is simply an equipment malfunction. They eventually find Briggs safe downriver. But Strode is suddenly attacked and dragged away by a large, strange creature. As Strode fights for his life, he grabs on to his water scooter and turns it on full speed, but the creature latches on to Strode and pulls him back into a dark crevice. The water scooter speeds off on its own and crashes into the cave wall causing a rock fall. The group start to look for Strode but Jack calls them back. He realizes the cave-in has now forced them to follow the river and search for a new way out. Dr Nicolai believes they should wait to be rescued, but Jack reminds Nicolai that they are three miles below the surface entrance and their support crew is not scheduled to retrieve them for 12 days. Jack and Top decide to follow the river together along the line left by Strode. Jack is seized by one of the creatures that attacked Strode, but is able to fight it off. When the men make it back to the team, Jack has three deep cuts on his back, as well as a huge claw he severed from the creature. Kathryn looks at cells from the claw under a microscope and notices a mutation within them. She realizes the mutations indicate the presence of a parasite. Nicolai discovers the same parasite in all of the lifeforms they find. The known cave species all originated above ground, she explains, but have adapted over generations to life underground. Kathryn theorizes this new parasite originated in the cave environment and has never been exposed to the outside world. The team stumble across the equipment and remains of previous explorers and also find a femur bone with large teeth marks, unaware they are themselves being stalked by the creatures. The team is obliged to descend through a series of rapids. Tyler sees Nicolai hanging on to the side of the cave, his leg badly injured, but is sucked down into the current, before he can help. As everyone starts to surface, they hear Nicolai screaming. Jack volunteers to retrieve him and