- Richard Lumley (First appearance)
- SSR (Mentioned)
- Bucky Barnes (Mentioned)
- Hydra (Mentioned)
- Project Centipede (Mentioned)
- A.I.M. (Mentioned)
One night by an academic facility pool, Donnie Gill is interrupted in his studies by the appearance of several youths looking to use the pool after hours. Donnie ignores them, at least until the girl Callie notices the pool rapidly freezing behind her classmate Seth, and warns him to get out. Seth’s leg is briefly trapped in the ice until the others free him, placing a S.H.I.E.L.D. towel over the frigid student.
Back on the bus, Coulson obsessively pours over the files of his demise, while downstairs Fitz and Simmons reveal that they created the device that nearly froze a student, and have been tasked with returning to the academy to investigate. Upon arrival, Fitz and Simmons find themselves popular among the scientific academy’s students, while Ward greets Agent Weaver in hopes of interviewing the student nearly killed by the device, trying to find the “bad seeds” that might want to harm their fellow students.
May advises Coulson to stop obsessing over his files, instead focusing on their own mission to Mexico City, tracking down the former S.H.I.E.L.D. agent partnered with the woman who dropped Skye off at the orphanage before dying. Meanwhile, Ward brings Skye to see the facility’s “Wall of Valor” while Fitz and Simmons begin a lecture to the students about the danger of potential. Midway through the lecture, Donnie finds himself freezing over, soon completely encased in ice. As Fitz and Simmons work to free him, Skye smashes the device causing the cold, thus saving Donnie. Elsewhere, Ian Quinn converses on the phone with an unseen figure, wondering why the device didn’t work.
Donnie can think of no one who might want to target him, as Agent Weaver corroborates that Donnie has neither friends nor enemies. Ward sends Fitz to befriend Donnie and see what he can learn, while he, Skye and Simmons head to an underground boiler room bar where the students frequently let off steam. Meanwhile in Mexico City, Coulson and May set up in an alley to wait for former agent Richard Lumley, while Coulson notes that Melinda has been talking more than usual to compensate for his stony silence. Just as May goes to share the secret she’s been keeping with Ward, Coulson spots Lumley across the street, and the pair pursue him. After a brief tussle with May, Coulson drives up in Lola as Lumley climbs a fire escape and switches to hover mode. Relieved to see that they're S.H.I.E.L.D., Lumley guesses they want answers about the "baby girl."
Back aboard the Bus, Lumley reveals that Skye herself was an “0-8-4” that an entire Chinese village had died to protect, while the agents tasked with protecting her were slowly killed off by some inhuman force. His partner, Linda Avery faked a Level 8 system to hide her existence by shuffling her around to different orphanages, shortly before she was killed. With his story concluded, Coulson decides that they'll have to relocate Lumley, who warns them to stay away from Skye, stating that death follows her. May urges Coulson not to tell Skye the truth, while back at the academy, Fitz visits Donnie in his room to bond with him, helping him to complete a complex power source he’d been designing in his spare time. Over at the bar, Ward speaks with Callie about how excited Seth and Donnie had been to meet Agents Fitz and Simmons, leading the team to realize they’d staged the attacks to get Fitz’s input on how to fix their device. Once Fitz is alerted to the news, he finds Donnie working on a much larger freezing device, before Seth knocks him out.
Skye and the others put together that Seth and Donnie must have had a backer in building the device, likely that of Ian Quinn, whom Seth’s father works for. The boys meanwhile contact Quinn looking for an extraction now that they've been compromised, but Quinn suggests they turn on the device as proof of its worth. Back on the plane, Skye confronts Coulson about his ignoring her, to which Coulson decides to tell her the truth about her history. Outside, it begins to hail as Donnie and Seth’s device creates a super-storm around the academy.
Once the storm grows beyond control, Donnie desperately attempts to shut the device down, before its explosion sends both of them flying backward. Overhead, May manages to pilot their plane directly into the eye of the storm, allowing the team to retrieve Donnie and Seth, though Seth ultimately dies of his injuries, before the storm finally dissipates.
In the aftermath, a bitter Donnie is sent to the Sandbox for observation, while Coulson acknowledges to May that he heard her earlier confession about Ward, and trusts her to break it off with him if necessary. Skye revisits the Wall of Valor on campus as Coulson marvels to May that Skye didn't allow the revelations to destroy her, but rather took comfort in the fact that she’d had a S.H.I.E.L.D. family looking out for her all her life. Awhile later, Donnie realizes he can freeze the window of his transport, while Coulson calls Ian Quinn to warn him of their next confrontation. Before Quinn hangs up however, he reveals that the Clairvoyant wanted him to say hello.
- In the comics Donnie Gill is also known as Blizzard, a supervillain with a powered suit that provides him the ability to produce Ice and cold. He is a long time foe of Iron Man.