A lethal government operative who tracks and stops terrorist threats before they occur finds herself on the run – and the new focus of Reese and Finch's attention. However, their pursuit proves to be their most formidable when they discover that her remarkable skill set equals their own.

As Reese and Shaw race to catch up with Finch, he infiltrates a maximum-security government facility in a desperate mission which could mean the end for not only Samaritan, but for himself and The Machine as well.