A bound, gagged girl, encased in a full-body cast, is suspended from the ceiling, her body swaying gently. A sadistic doctor has her bouncing on a metal spring, her weight causing it to dip and rise, making her helplessly grind against a massive, vibrating dildo planted on the platform below. Her moans are muffled by the gag, but her eyes gleam with masochistic pleasure as she's used like a sex toy, her body trembling with each thrust of the relentless machine.