Episode 12 in season 2 of "The Strain" marks the beginning of hope in humanity's fight against the strigois. The Occido Lumen is finally up for bidding and Eph finds a way to turn the vampire vaccine as bio warfare.

Episode 12, titled "Fallen Light," opens with a flashback scene that takes viewers back to how Eph and Nora met during the Infectious Disease Conference in Washington. During a panel discussion, Nora questions Eph's measures in controlling the spread of infectious diseases. However, instead of taking insult, Eph found Dr. Martinez's confidence and intelligence useful, so he hired her to work with him.

Another flashback scene shows how Eph and Nora have been battling their feelings for each other. All throughout their working relationship, the two have tried to remain friends. Eph has been confiding with Nora about his strained marriage with Kelly and about his battle to gain custody over Zach. Eph tells Nora after dinner that Kelly had filed for divorce and gained full custody of Zach. Nora finally confronts Eph about their love for one another and they kissed.

Back in the present, Zach, Nora and Eph received good news that Zach's grandparents are still alive in Georgia. Zach gets to talk to them on the phone, crying as he tells them how he misses them. Eph takes this as a sign to prioritize the safety of his son over the security of the people in New York. However, he and Nora came up with a plan that could work both ways.

They convinced Justine to allow them safe passage out of the city to take Zach out to Georgia. Justin agreed. As an exchange, Eph and Nora promised to give Justine the vaccine they created to be used as bio warfare against the strigois.

Justine, on the other hand, is suspected of murdering the mayor after they were overheard getting into a heated argument over her indictment. She claimed her innocence and entrusted his commandant to find whoever killed the mayor. She was then appointed as director of security following the mayor's death.

"Fallen Light" also showed Setrakian finally agreeing on a bidding war with Palmer over the Occido Lumen. However, Eichorst will be bidding on behalf of Palmer, according to The Master's wishes.

Setrakin gets the assurance of gold from Quinlan as payment for the book. However, Quinlan fears Setrakian would use the Lumen to kill the Ancients. So he orders Gus to get the book from the old man after the bid, even if it means killing Setrakian.

Episode 12 in season 2 of "The Strain" ended with Eph and Nora questioning their relationship. An emotional Eph tells Nora that he still loves her. Nora then goes to her room crying. She suspects that Eph may have been unfaithful to her during his visit to Washington.