Shipwrecked on a remote beach, Ryan and Josh must overcome their differences in order to outwit a mysterious and dangerous new enemy. Meanwhile, Jarrah and Gabe search for Zuke.
After Dionne shows Ryan the tragic consequences that have befallen those trying to cross the desert, Ryan disposes of the antidote to stop everybody leaving, only to discover the hope it symbolises.
Ryan is guilt-ridden when a life-or-death situation pushes him closer to Jarrah. Meanwhile, Natasha's relief at being reunited with her friends is short-lived when she suspects that something has happened between Ryan and Jarrah.
When Saskia is revealed to be one of the Snatchers, she attempts to make amends. When this fails, she is left with no choice but to leave the community.
Despite her anger towards Ryan, Natasha realises she still cares for him after he endangers himself trying to rescue them. Lily and Josh get swept out to see while fishing, and a fleeting glimpse of a boat offers a brief hope of rescue.
When Eli learns about the existence of the antidote, he manipulates the situation to secure it in his possession. Ryan tries to cheer up Bonnie after she is bitten by a sea snake.