Longtime girlfriends Sarah and Lou prepare for an island camping holiday. Unbeknownst to Lou, Sarah has arranged for estranged friend Abby to join them in hopes of mending the friendship between Abby and Lou. Sarah pretends to have terminal cancer in order for her friends to agree to a weekend together. Once they consent, Sarah reveals that she was only kidding about cancer.The girls take a small boat to the island of Black Rock. Sarah gives each girl a "Goonies" map they made as children that leads to an abandoned cabin. While hiking, Abby argues with Lou and it is revealed that Lou once had sex while drunk with Abby's boyfriend, although Abby has since married another man.Back at their campsite, the three women encounter three hunters. One of the men turns out to be Henry Wallace, whose older brother Jimmy went to elementary school with the girls. The other two men are Henry's Army buddies Derek and Alex. All six men and women eat and drink together around a campfire. The girls learn that the men are only three weeks removed from their most recent tour in Afghanistan, and Derek and Alex are fiercely loyal to Henry for saving their lives.While drunk, Abby flirts with Henry. Later, they go off together in the woods and start making out. When Abby starts resisting, Henry forces himself on her until she takes a rock and accidentally kills him. The others are alerted by Abby's scream and then they find the body. Distraught, Derek gets his gun and threatens the women. They start to run, but Derek and Alex are able to knock out and capture the girls.In the morning, Abby, Sarah, and Lou awaken to find themselves tied up while the two men argue about what to do with them. Derek unties Abby so that he can fight her. The other women then take the opportunity to run. Derek and Alex chase all of them into the woods. The girls eventually reunite at the abandoned cabin from their map.After waiting until dark, the girls crawl to the shoreline in search of the men's boat. They discover that the men cut the mooring rope. The boat has drifted out and the water is too cold to swim. The girls decide to swim anyway, but when Sarah hesitates and returns to shore, she is shot and killed. In the dark, Alex falls and injures his leg. Abby and Lou swim back to land and remove their wet clothes to avoid hypothermia. Once they have regrouped, Abby and Lou find a time capsule they buried as children that contains a small pocketknife. The girls then reconcile their past while fashioning spears.The next day, Abby and Lou don their dry clothes and stalk the men at the beach. Alex alerts Derek when he hears Abby sneaking up on him. Lou runs into the woods to distract Derek and lure him away. After a struggle, Abby retrieves Alex's gun and kills him. As Derek prepares to shoot Lou following a chase, Abby tackles him and the gun jams. The two girls then fight Derek and he stabs Lou in her stomach with a stick. When he turns his attention to Abby, Lou recovers Derek's knife and slits his throat. The wounded girls then take the boat back to land.