The plot follows the Fringe team's investigation into ZFT and David Robert Jones, who claims that Olivia is a soldier equipped with abilities to fight in an upcoming war between two parallel universes.
Jared Harris guest-starred as Jones, alongside actors Clark Middleton, Michael Gaston, Noah Bean, and Chance Kelly.
Meanwhile, Olivia postulates that the initials "ZFT" may not be of a terrorist organization but of a book, and discovers the German name, "Zerstörung durch Fortschritte der Technologie", roughly "Destruction by Advancement of Technology".
Suffering from effects of being teleported out of his German prison cell by Walter's technology, he insists on only speaking to Olivia, warning that she is the only one that can stop a bomb from going off in 36 hours.
In the interrogation room, Olivia discovers that Jones believes she is one of the soldiers in his war, having been a test subject on a Massive Dynamic nootropic drug known as "Cortexiphan" when she was a child.
Olivia, having learned from Nina Sharp that the only Cortexiphan trials were done in Ohio, far from her childhood Jacksonville, Florida home, is confident Jones is mistaken.
In the episode's epilogue, Jones, having been transferred to secured hospital, is rescued by his men, leaving a message on the wall telling Olivia she passed.
Olivia receives a call from Nina who had further looked into the Cortexiphan trials and discovered a smaller case study that occurred at Jacksonville.
[1] "Ability" was watched by an estimated 9.83 million viewers on its initial broadcast in the United States, placing in second in its timeslot behind CBS' The Mentalist.
Den of Geek viewed the episode positively, observing that in contrast to the previous installment, "Ability" "progresses the main plot arc in a substantial way... I’m now really interested to see what happens next, whereas last week I wasn’t that bothered.
He noted that though the ending with Walter "was as good as you could ask for" and enjoyed David Robert Jones as a villain, the episode had a "number of rough patches," as the middle was "paced slowly" and lacking in suspense, Peter's "handiness was again reduced to ...'that guy with connections'", and the audience was "once again subjected to the torture that is Sanford Harris".
[13] After describing the Olivia-Peter scene near the end as "tense and cleverly written," Isler concluded his review by noting references to The X-Files and hoping Jones would appear again soon.