Cristina and her family are finally headed to Mictlan, the peaceful afterlife. Not wanting to see her go, Victor beckons her to pull one last troll on Don Jalapeño with him, though Valentino quickly suspects his duplicity. Cristina misses her train, so the boys swipe Sal's flute and transport themselves to the ninth realm, only to run afoul of the Bone Boys who send them on a journey. Victor acts incredibly selfish and Valentino is constantly worrying, but must work together if they are to help Cristina reach the ninth realm. They must traverse a lake of lava to reach an island, run through twin stone mountains that are slowly closing in on them and fight their dark reflections who attempt to trap them in dark mirrors for eternity.