While training for the upcoming World Championship Junior Cup in Lacunosa Town, after the battle with Pignite and Mamoswine, Ash, Dawn and the others meet a young boy that Jervus knows who lives in the neighborhood in Undella Town named Chris. He apparently lost his Cubchoo just this morning when it disappeared from his family's Pokemon house to the outside. So Cilan, the Master Detective Connoisseur is on the case to solve The Mystery of the Missing Cubchoo. Will he find the Cubchoo? Yes, until they find out that Chris' Cubchoo was playing with a Larvitar all along since they became friends to each other.