Purgatory

Nick confronts Emma, and Dr Serob explains his relationship with Alex. Meanwhile - The search above ground begins after both Preston and Ophelia receive worrying information about their children.

Bobby swears revenge over the death of his friend. Concerned about her husband, Marie goes in search of Chris. Bobby confronts the others about Nick's death and everyone splits up unsure whom to trust. Bobby seeks an alliance with Emma.

The search continues with Preston enlisting powerful allies. With their supplies destroyed, the group has to decide their next step. After waking up with a gun beside him, Bobby wants answers. Dimitri is caught in a trap set by their host.

Marie is not doing well underground. Lisa and Kat decide to join Bobby and the trio makes a startling discovery. More discoveries are made as to why each person is there and their relationship to the death of Alex.

After the death of Kat, Lisa is left alone with Bobby. Without medication, Dimitri's condition continues to deteriorate. Ophelia and Inspector Popa hit a dead end and decide to go to the press, but Preston recognizes a name.

Two different views of the puzzle leave Bobby and Lisa wondering what is next. Marie searches for answers and Emma's truth is finally revealed, forcing Chris to confront the demons of his past.