In 2121 A.D., Yefet was apart of the command staff on the Cobra of a task force, comprising Able, Delta and Echo Squads for a Recon-and-Force Mission to Mars to locate a new massive underground Neosapien Weapons Complex.
The mission was a trap, set up by Neosapien Spy Barca, and Delta and Echo Squads took heavy causalities. Yefet was an accomplice to Barca's action and was killed when an attempt to assasinate Admiral Winfield and Jonas Simbacca back fired, causing their ship, the Cobra, to be destroyed by their rigged explosives rather than their intended target. Yefet and Barca were on the Cobra and died in the subsequent explosion.
- Episode 35 - Fire Ship