Losing Gemma

Esther and Gemma meet in a nightclub through a mutual friend who is supposed to be going to India with Gemma. When the friend breaks her leg and can't travel, Esther steps in to accompany Gemma. The first part was genuinely unsettling as the pair meet Zac and Gemma and are invited on a boat trip with them. Esther is suspicious of the couple, but Gemma, presumably being more naive, doesn't share her suspicions.