When the girls are once again summoned for another fight Rachel loses her sanity and escapes. Kate and the others follow after her, learning from Lula that if even one of them strays from the group during a mission then all will die. Rachel is found and brought to her senses but has lost the will to live. Lula offers the girls a hope to return back to their former lives, but the cost involves showing them the grisly truth.

ごく普通の生活を送っていた少女たちにとって、命のやりとりは荷が重すぎる。召集を前に、耐え切れずに逃げ出してしまうレイチェル。その矢先、ケイトに教えられた、新たなルールとは「連帯責任」だった。必死にレイチェルを追い掛けるクレアとローズ。そして、驚愕の真実が幕を開ける・・・。