Captain Rainbow Dash must seize the fabled Dead Stallion's Chest or else be sent to Spike Jones' Locker. Meanwhile, Shining Armor must find Rainbow Dash or else he and Cadence will be hung.
Sonata Dusk has turned to the Dark Side for revenge, and Adagio is the only one who can stop her. Who'll help her out on her adventure, however, is quite a surprise. Savvy?