With his health failing, Setrakian ignores Eph's warnings and pushes himself to the limit in his quest for victory and revenge; Fet and Quinlan race back to Manhattan, while the Master seals off the city and prepares to eliminate them all.

Reeling from loss, the heroes regroup; the heroes devise a new plan to track the Master through human collaborators, beginning at the blood farm with someone Dutch knows all too well.

An unexpected guest brings old conflicts to the surface, dividing the heroes and threatening the group's trust; with questionable new intelligence in hand, the group launches a make-or-break final assault on the Master.

In the series finale, Quinlan devises a desperate plan, but the costs are enormous. Eph wrestles with his conscience, Fet undertakes a suicide mission, and Dutch and Gus dig in for battle as humankind makes its final stand against the Master and his Strain.