In a very strange fantasy world, there are those that set out be Adventurers or more over Monster Users: Humans who can control said beasts with certain instruments (usually a guitar) and increase their power. However not all monsters in this world are visible to the human eye, some move around in human form either voluntarily to keep their powers in check or are forced into it to keep certain ones from going wild. The latter is the case of Keel, a Dragon Ape (yes you read right) who's stuck in human form and searching for a individual name Shiva who put him in such a predicament (the reason why is unknown however). As the story opens he meets Lavie, a female monster user and her flying pig monster, Mippy. After certain events, the two decide to work together to find Shiva (both with their own reasons for doing so) along the way they meet Blue, a ninja and later revealed to be a water demon who's on his own quest and soon all three of their goals collide and the foursome form a party together. Say the least, Shōnen adventure ensures.
This manga provides examples of:
- Bitch in Sheep's Clothing: Lily, Keel's adopted mother. But she pulls a HeelFace Turn and gave her life for him and his adopted brothers.
- Catchphrase: Keel: "Funky!". Blue: "Bingo!" (...Yeah don't ask)
- Dem Bones: The aptly named "Bone"
- Enemy Mine: The protaganist teaming with Tattoo and Bumper against Jack
- Everything's Better with Monkeys: Considering that Keel's original form...
- Expy: Heartful -> Heartfilia?
- Heroic Sacrifice: Crem, she resurrects as its an ability of her species but loses her memory of her time with Keel
- Mons: Namely to Monster Users like Lavie
- Overly Long Name: Mippy real name is Mishishippi Teramoto, once can't blame Lavie for going with the nickname
- Poor Communication Kills: Had Keel bothered to the tell the Monkey Brothers about Lily's nature sooner, they wouldn't have wound up joining the organization that they were mean to be sold too in the first place.
- The Power of Rock: Most of the ways to power up a monster.
- Shapeshifter Mode Lock: The main reason for Keel's quest is to find a certain music to undo his transformation Shiva put on him.
- You Killed My Father: Keel's adopted brothers think he did this when they had walked in on him standing over their adopted mother's body in the past Turns out, no he didn't. Keel had discovered their mother's true nature and she had killed herself to both to apologize for lying to them and to keep them out of her evil organizations hands. It was just a case of bad timing on the brothers' part. Not helped that Keel went tight lipped when they had asked him about it.