Description: The Scalar Theory of Everything (STOE) model of photons is extended to model the inertia of mass. The characteristic of the plenum, hods, and their interactions yields the Newtonian characteristics of gravitational mass and inertial mass. The medium of the wave in the Hodge Experiment was the massless plenum. The plenum is the carrier of the inertia. The hods are the carrier of the gravitational mass. The Equivalence Principle is derived rather being assumed. Mach's Principle is inconsistent with the STOE.