After being tasked with saving the life of a potential bio-weapons terrorist, two London scientists find themselves in a locked-down laboratory with time - and air - running out.

After the tragic death of her son, Arlene loses everything, her husband, her home and she starts to lose her mind. When the mysterious Endeavour Institute offers her a chance to travel back and change things, she eagerly accepts and begins her journey to the past. Plagued by the memories of her alternate reality, Arlene must separate the real from the false without upsetting the delicate balance. She is unprepared for the terrible price she must pay for saving her son.