At 13, Serena became the Kalos League Champion, rocketing her into stardom, fame, and glory. Unable to settle down permanently in Kalos just yet, possibly (probably) due to trauma, Serena heads to Hoenn under the guise of studying the origins of Mega Evolution, only briefly returning to Kalos to handle Champion affairs when absolutely needed.

Five years later, after seeing a very odd promotional video for Hotel Z, Serena is stunned. AZ, the 3,000-year-old giant homeless senile war criminal who interrupted her Champion parade, owned a HOTEL?! Serena decides that a stay in Lumiose is in order immediately. What was supposed to be a drop-in visit quickly spirals into another massive undertaking, featuring a wide array of new and fun colorful megalomaniacs, and training a brand new team.

At least this time, it was just the fate of Lumiose on the line, not the destruction of the entire world and every life form on it. Small victories.