Victor and Valentino chase after a strange chihuahua named Achi, only to get trapped in an underworld labyrinth by the Keepers of the Dead. Now they must learn to work together in order to survive.
- Be Careful What You Wish For: During an argument, Victor angrily wishes that Valentino was dead. Then it happens (luckily, Valentino is brought Back from the Dead).
- Broken Masquerade: At the end, Victor and Valentino discover that there are spirits all over Monte Macabre, and their Abuelita is some sort of Aztec deity.
- Canon Discontinuity: The series itself does its own take on the protagonists' first journey to the Underworld, and plays coy with Grandma Chata's possibly supernatural nature. It doesn't explain how the duo know Achi, however.
- Chekhov's Gun:
- The luchador mask Victor buys at first appears useless. When the guardians of the Underworld are about to take them, Victor puts on the mask and attacks... but the mask grants him no special powers, and he loses. Then when they get back, he finds that the mask lets them see the secret Spirit World around them.
- The tacos that Valentino made earlier. When Victor flings one at one of the guardians, he takes a liking to it and both of them agree to let the brothers go in exchange for the recipe.
- Early Installment Weirdness: The pilot is more focused on the underworld, whereas the series focuses on Monte Macabre itself, generally avoids the supernatural creatures being Invisible to Normals, and Chata's supernatural nature is also plainly spelled out, whereas the series primarily (albeit sometimes blatantly) hints at it.
- Follow the White Rabbit: Victor and Valentino follow an Achi, an undead Chihuahua, down into the Underworld.
- Insult Backfire: Valentino calls Victor obtuse, or stupid. He thinks it's a compliment.
- The Little Shop That Wasn't There Yesterday: In the maze, the duo find a souvenir stand run by a Chupacabra. It sells various items that could help them get out of the maze, but Victor buys a luchador mask instead, and the stand disappears right after.
- See-Thru Specs: The luchador mask Victor bought in the maze allows the two to see the spirits roaming Monte Macabre, along with the spiritual form of their grandmother.
- Talking Dog: Achi is a talking chihuahua. Justified, as he's dead and supernatural.