Super Alicorn Sisters: Return of the Tantabus

After the Tantabus, the dream monster that threatened to turn Equestria into a living nightmare, was defeated, Princess Luna thought she could finally sleep peacefully, but it turns out that the Tantabus wasn't actually defeated. Parts of it escaped into the real world, and the parts have been giving ponies all over Equestria nightmares. Can Celestia and Luna venture across Equestria, destroy the Tantabus particles, and save everypony before it's too late?