Best Laid Plans is the ninth episode of the fifth season of the television series Agents of S.H.I.E.L.D., and the ninety-seventh episode overall.

Synopsis

Mack, Yo-Yo, and Flint fight to keep everyone alive by starting a revolution against the Kree.

Plot

Alphonso Mackenzie and Yo-Yo Rodriguez successfully initiate a rebellion against Kasius and the Kree Watch, killing eight Kree guards after gathering the Lighthouse's inhabitants like Gunner. Upon learning that the Humans survived the Vrellnexians and are rebelling, Kasius decides to send a messenger: Tess, who was revived through Kree technology. Tess informs Mackenzie, Rodriguez and Flint that Kasius intends to blow up the entire Lighthouse if the S.H.I.E.L.D. agents, Flint as well as all the children older than ten are not delivered to him. While Flint and Yo-Yo advocate for a frontal assault, Mackenzie and Tess advise caution.

Mackenzie figures out that Kasius rigged the Lighthouse with bombs scattered all over the place, enabling him to incinerate all the Humans by pushing a single button. Together, the Humans devise a plan to counter Kasius and send Tess back to him, asking for a meeting. Kasius reluctantly agrees and Mackenzie and Rodriguez threaten to destroy all his scientific equipment for breeding Inhumans if he does not hand over the bombs controller.

When Rodriguez fails to take it by force, Kasius pushes the button. However, the S.H.I.E.L.D. agents reveal that they were only stalling so that the other Lighthouse inhabitants could take all the bombs to the same place and hide far from the detonation. After Tess escapes from the Kree Watch, Mackenzie blows up Kasius' equipment and Kasius screams out of rage.

On the surface of the Earth, S.H.I.E.L.D. prepares to face a gravity storm by repairing the Zephyr One to make it fly again, much to Enoch's surprise who thinks that it will lead to their deaths. Meanwhile, Deke Shaw confronts Samuel Voss about the death of his father and intends to kill him, but Voss advises him against it and tries to convince him to turn on the S.H.I.E.L.D. agents. Deke chooses to spare Voss and leaves, uncertain about what to do.

As the gravity storm approaches, Quake tells Coulson that she should probably remain deprived of her powers for everyone's safety. Elsewhere on the plane, Leo Fitz and Jemma Simmons discover that the Zephyr One has been upgraded with Fitz's old designs for a new plane, including artificial gravity generators using Gravitonium. To Fitz, Gravitonium could explain what happened to the Earth, but it also means that they are facing a causal paradox and that they will fail saving the Earth, reconnecting with his theory that the future cannot be changed, although Simmons disagrees.

Deke returns to the team and informs them that he spared Voss. With the gravity storm soon on them, S.H.I.E.L.D. try to take the Zephyr One in the air, but the engines are too damaged, blocking them on the ground. S.H.I.E.L.D. sends the True Believers to hide and find shelter in the caves. Unbeknownst to them, however, Sinara infiltrates the plane. After seeing that the gravity storm has reached them, Simmons suggests to take advantage of it and the Zephyr One's upgrades to fly without needing the engines. S.H.I.E.L.D. decides to follow Simmons' idea, but the anchors keeping the plane on the ground get stuck.

Quake, who is followed by Deke, decides to go and fix that, but she is found by Sinara. As the plane finally takes off because of the storm, a violent fight erupts between Quake and Sinara and Sinara nearly kills Quake before Deke chooses to rescue her, definitely siding with S.H.I.E.L.D. Quake ultimately kills Sinara with an improvised spear.