[This is a review of Agents of S.H.I.E.L.D. season 4, episode 18. There will be SPOILERS.]

Agents of S.H.I.E.L.D. season 4 has taken a break from reality for its third storyline arc (or, as those close to the show call it, pod) of the year, instead opting to explore the virtual reality of The Framework. After introducing the Darkhold through the first pod, which followed Ghost Rider, then seeing Radcliffe and his Life-Model Decoy Aida work to obtain the ancient text, the show has delved into the alternate world created by Radcliffe and Aida thanks to the help of the Darkhold. In The Framework, Aida "fixed" some of the S.H.I.E.L.D. agents' biggest regrets and let the world play out as a result of those changes.

The biggest impact Aida's changes had on the world was, of course, the victory of Hydra in their takeover of the United States within the Marvel Cinematic Universe. On a more personal level, Grant Ward (guest star Brett Dalton) is a Resistance agent rather than a Hydra operative, Jeffrey Mace is an actual Inhuman and the leader of the Resistance, and Fitz is the evil Doctor for Hydra -- he's also dating Madame Hydra (played by Aida actress Mallory Jansen). Now, the world of the Framework, and the consequences of what happens in this virtual reality, become even more real as Simmons and Daisy work to escape.

In this week's episode, 'No Regrets' -- directed by Eric Laneuville and written by Paul Zbyszewski -- Mace and Coulson attempt to rescue Daisy but wind up infiltrating a Hydra Enlightenment Cultivation Center in an effort to save a fellow Resistance member, one who fans will recognize. Meanwhile, Simmons tries to explain the Framework to Mace and Ward while Fitz's regret is revealed and Daisy makes progress though she's still imprisoned by Hydra.

The Patriot Sacrifices Himself

The main thread of 'No Regrets' focuses on the Resistance's efforts to free Daisy from Hydra, but Mace also emphasizes the need to recover one of their agents who had been working in Hydra and been found out. This particular agent, as it's revealed halfway through the episode, is none other than Antoine Triplett (B.J. Britt), the mid-season 1 addition who died in season 2 when he and then-Skye discovered Terrigen crystals. Within the Framework, Trip still hails from a member of the Howling Commandos and became a key member of the Resistance.

In fact, Trip's return in 'No Regrets' is especially poignant as his character died in season 2 while trying to save Skye from the effect of the Terrigen crystals (not knowing at the time that they were relatively safe for her), sacrificing himself. This particular death scene mirrors the sequence later in 'No Regrets' that sees Mace sacrifice himself to hold up a crumbling building until Coulson, Ward, Simmons, May, and the children being held by Hydra were able to escape. It's an emotional scene, with Elizabeth Henstridge's performance especially captivating as Simmons realizes she's unable to save Mace from dying both within the Framework and without.

Simmons spent much of 'No Regrets' - and most of her time in the Framework as a whole - refusing to believe anything in the Framework matters since it isn't the reality she knows. While Coulson believes Simmons, Ward and Mace have trouble abandoning the reality they know - which, whether or not it matters, the Framework is arguably better for both of them. In Mace's case, he was the Inhuman hero his real self could only aspire to be. Giving the Patriot a hero's death when Mace himself often simply pretended to be a hero is an especially tragic end to the character's arc on Agents of S.H.I.E.L.D. But, with 'No Regrets' taking care to show that Mace died both in the Framework and in the real world, it additionally sets up dramatic stakes for the run up to the season 4 finale.

Fitz’s Secret Is Revealed

As with Mack and his daughter Hope, Agents of S.H.I.E.L.D. began laying the groundwork for Fitz's life in the Framework since earlier on in the season. The show began teasing the significance of Fitz's father in the second season 4 pod, with the LMD version of Radcliffe mentioning that he had known Fitz's father. Fitz later revealed that his father left he and his mother, and they didn't have much of a relationship. However, in the Framework it seems Fitz was raised by his father rather than his mother - and Alistair Fitz (David O’Hara) is the reason his son became Hydra's Doctor rather than the man Simmons loves.

The reveal of O'Hara playing Fitz's father is somewhat anticlimactic since the character is introduced in a scene as someone with which Fitz is discussing a security breach (the breach being Trip using one of his grandfather's cameras to steal plans for Project Looking Glass). Then, it shifts as their conversation becomes more personal, and Alistair throws in a mention of "my boy," which drives the reveal home a bit too hard. Plus, O'Hara uses his Scottish accent as Alistair, which takes the wind out of the sails of the show's reveal since he's the only Scottish character to be introduced on Agents of S.H.I.E.L.D. since John Hannah as Radcliffe.

That said, the scenes between O'Hara and Iain de Caestecker as father and son are compelling and it's fascinating to see how Fitz's father's influence has impacted who he is and what he's willing to do. Of course, now that the dynamic between Alistair and his son has been introduced as the reason for Fitz's actions, Agents of S.H.I.E.L.D. will no doubt explore whether Fitz is able to change - perhaps if he meets Simmons once again.

May Turns Her Back On Hydra

Since the first episode of Agents of S.H.I.E.L.D. that took place within the Framework, the show has established May's part in how the history of the world played out - and the guilt she struggles with as a result. However, while May seemed to be a dedicated Hydra operative, 'No Regrets' sees her resolve waver, especially when she's confronted with what the organization is up to at their "Enlightenment Cultivation Center" - particularly after Fitz gave the go ahead for a Quinjet to take down a building in which kids were being held.

Her beliefs are further challenged by Patriot, who she believes to be a terrorist and a thug. She even goes so far as to take what is essentially Mace's super-soldier serum from reality in order to have the strength to take on Patriot in the Framework. But, instead of killing May, he leaves her after besting her in a fight, then sacrifices himself in order to save everyone else in the crumbling building. These acts of heroism seemingly inspired May, and she betrays Hydra by breaking a Terrigen crystal inside Daisy's holding cell.

For her part, Daisy spent her time in Hydra lockup learning everything she could from Radcliffe on how to escape the Framework. Now, with Daisy receiving her Inhuman powers, she'll be able to put up a real effort to break out and return to her friends so that she and Simmons can escape the Framework. After 'No Regrets', there are only four episodes left of Agents of S.H.I.E.L.D. season 4 so Daisy and Simmons' days inside the Framework are likely numbered. But, they still have Madame Hydra and her Project Looking Glass to contend with - not to mention Aida and her army of LMDs once they do finally escape the Framework.

Next: Agents of S.H.I.E.L.D. Season 5 Renewal Looking Good

Agents of S.H.I.E.L.D. continues Tuesday April 25 with ‘All the Madame's Men’ at 10pm on ABC.