Sarah hopes that cleaning out a dead woman's bank account will solve all of her problems. Instead, her problems multiply - and so does she. Starring Tatiana Maslany in the lead role of Sarah, an outsider and orphan whose life changes dramatically after witnessing the suicide of a woman who looks just like her. Sarah assumes her identity, her boyfriend and her bank account. But instead of solving her problems, the street smart chameleon is thrust headlong into a kaleidoscopic mystery. She makes the dizzying discovery that she and the dead woman are clones...but are they the only ones? Sarah quickly finds herself caught in the middle of a deadly conspiracy, racing to find answers.
Cosima takes a turn for the worse, forcing Sarah to take desperate action – with tragic consequences for those she loves. The Proletheans set their ultimate plan in motion. Alison and Donnie tangle with the law.