In Scotland, the Joes become trapped in Destro's castle while on a mission investigating a Cobra weapon.

A Cobra commander is attacked by a ninja and forced to escape to his secure facility. Meanwhile, Snake Eyes and Scarlett sneak into the commander's facility.

Cobra plans to increase its power by deploying the MASS device, but Scarlett plays a key role in its operation.

The Joes attack Cobra to stop the use of a dangerous device, expose its owners and clear the team's name.