We knew that Marvel's Agents of SHIELD was going to be heavily focused on the idea of infiltration by life model decoys when it announced the next storyline would be titled Marvel's Agents of SHIELD: LMD, but the most recent episode of the series takes that to an entirely new level.
SPOILERS for the Marvel's Agents of SHIELD episode titled "The Man Behind the Shield" follow.
"The Man Behind the Shield" was centered on Phil Coulson launching a full-scale rescue mission for Director Mace and Agent May.
Fitz and Simmons were able to track Mace and May to an abandoned soviet detainment center and submarine port that the Superior was using as a base, then joined Coulson, Quake, and Mack in infiltrating the base. It turned out that May was still being kept on the Submarine, which managed to depart before the SHIELD team could reach it. The team did manage to retrieve Director Mace.
However, Simmons later realized there was something strange about the mission's timeline. There was an extended period of time when Simmons and Fitz lost contact with the rest of the team that doesn't match up with the series of events they were told once the team did meet back up.
It is then that Simmons and Fitz are notified that the LMD detection security upgrades Fitz had installed had been disabled and the records tampered with. Simmons used her high-security clearance to inspect the clearance and finds that it was Coulson himself who did the tampering.
Simmons pulled up the record that Coulson had singled out. The video showed Coulson, Mace, Mack, and Quake all entering SHIELD headquarters at the same time. The LMD detector indicates that four LMDs are present.
That means that Phil Coulson, Jeffrey Mace, Mack, and Quake have all been replaced by LMDs. On top of that, the Coulson LMD then reactivated the May LMD that SHIELD had previously discovered.
With that many life model decoys in positions of power in SHIELD, what Fitz and Simmons are going to be challenged to regain control of the organization.
Marvel's Agents of SHIELD airs Tuesdays at 10 p.m. ET on ABC.