SPOILERS for Agents of S.H.I.E.L.D. "Rise and Shine" ahead

The latest episode of Agents of S.H.I.E.L.D., "Rise and Shine," has finally revealed the history of General Hale and how Hydra fits into the Marvel Cinematic Universe timeline.

Introduced nine episodes ago, Hale has been a mysterious figure who plagued the S.H.I.E.L.D. team. Fans eventually learned that Hale is actually an agent of Hydra, a last survivor of Talbot's purge two years ago. But "Rise and Shine" dug a little deeper into Hale's history, explaining how she grew up in Hydra, and how she survived Hydra's destruction. Along the way, it also explained how Hydra fit into the overall continuity of the Marvel Cinematic Universe.

The Hydra Academy

Agents of S.H.I.E.L.D. has long implied that Hydra leadership is a family affair, passed down through generations. That seemed confirmed by adverts for "Rise and Shine," which featured Hale alongside the text "You can't help what you're born into." Like the Malicks or the Struckers, Hale was born into Hydra, and grew up under the Hydra regime.

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"Rise and Shine" introduced a whole new concept, though: the idea of the Hydra Academy. This installation was where Hydra's leaders sent their children, in order to both educate and indoctrinate them. After graduation, their children's skills and experiences were carefully assessed, and they were assigned duties - perhaps to join S.H.I.E.L.D., perhaps to enroll in the Air Force. Hale studied alongside Strucker and Sitwell, and after graduation was assigned to join the Air Force. This raises the possibility that Hydra, and perhaps General Hale herself, could be a background presence in Captain Marvel.

The final test before graduation is a hard one: Every student has to kill a dog that they raised. It's the same kind of test John Garrett put Grant Ward through in flashback sequences in the Season 1 episode "Ragtag." Garrett likely learned this at Hydra Academy, and it suggests he believed Ward could become a Hydra leader.

Hydra's Quest For Super-Soldiers

Agents of SHIELD Dove Cameron Ruby

Hydra has always been fascinated by super-soldiers. In 1989, Hydra had Daniel Whitehall released from jail in order to recommence his experiments on the Inhuman Jiaying. Whitehall learned how to extract Inhuman powers and transplant them into another person, granting himself renewed youth. This likely became the basis for a "Particle Infusion Charger," technology that would allow matter to be infused into a specimen's body. Seeking the perfect specimen to create Hydra super-soldiers, Whitehall had Hale undergo artificial insemination.

But what particles should be "infused" into Hydra's super-soldiers, and what powers should they be given? Ant-Man has already confirmed that Hydra were interested in Pym Particles. In a flashback sequence, Hank Pym stormed out of S.H.I.E.L.D. after learning their scientists were attempting to duplicate the Pym Particles. This was spearheaded by S.H.I.E.L.D.'s Head of Defense, Mitchell Carson, who was actually a Hydra agent. Certainly an infusion of Pym Particles - granting size-changing powers - would create a terrifying Hydra asset.

RELATED: The History of HYDRA in the MCU

A year after Hale's graduation, Hydra would learn that Howard Stark had successfully duplicated the super-soldier serum. As revealed in Captain America: Civil War, they'd bring the Winter Soldier out of cryogenic suspension, and have him assassinate Howard and Maria Stark. The retrieved serum samples were used to create a team of powerful assassins, but the subjects proved unstable; as Erskine had learned all those decades ago, the serum enhances the best and the worst in a subject. Hydra were forced to put their test subjects in cryogenic suspension, likely concluding that Whitehall's strategy - of deliberately creating and raising the perfect specimen - was the best approach.

Attempts to duplicate the Pym Particles evidently proved unsuccessful. Hydra's attention turned to Gravitonium, a new element that had just been theorized by Franklin Hall. Hydra chose to use one of Hall's friends, Ian Quinn, as a cat's paw to discover Gravitonium. Quinn began a quest to discover the rare element, one that would only prove successful decades later.

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"Rise and Shine" is filled with subtle details, ones that dovetail perfectly with everything Marvel fans have seen before. The episode presents us with our longest flashbacks yet to the time of Hydra, exploring just how the organization fits into the overarching story of the MCU. This is the kind of careful, deliberate continuity that has always made Agents of S.H.I.E.L.D. such a valuable part of the MCU.

MORE: Every Marvel Super-Soldier Program So Far

Agents of S.H.I.E.L.D. season 5 continues Friday, April 6th with ‘Inside Voices’ at 9pm on ABC.