Plot summary
Flashbacks depict Quinlan's past. An older woman, intrigued by Quinlan's strangeness, discovered him in a Roman gladiator camp. She believes he will "complete the prophecy". Quinlan tells Eph that the Master is his "father," but that he was conceived by humans. The Master infected his mother while she was pregnant, making Quinlan half-human, half strigoi. Killing the Master will result in Quinlan's own death. Angel discovers Gus is hiding his turned mother. When police "sweepers" inspect the building, they attempt to conceal her but are captured and conscripted to fight strigoi.
Fet and Setrakian track Eph and Quinlan to recover the Occido Lumen, using the GPS device Fet hid inside the tome. Eph demands that the Master meet with him to exchange Zach for the Lumen. During the exchange, Kelly tries tricking Eph with a "feeler" disguised as Zach. The Lumen ' s silver cover severely burns Kelly when she attempts to take it. Fet and Setrakian arrive and destroy the turned Navy SEALS that are aiding the Master. Quinlan beheads the Master, but a large crimson-colored strigoi worm crawls from the corpse and escapes. Eph and the others have the Lumen, but appear to have lost Quinlan.
Credits
Adapted from Wikipedia contributors, List of The Strain episodes. HTML formatting and reference markers removed.