Pokémon Mega Power is a fan-made role-playing game for Game Boy Advance set in the Ivara Region. Players assume the role of Neil or Tyra, a scientist striving to create an advanced version of Mewtwo capable of mega evolution without the usual mega stones. In need of resources, they ally with Kasper, the enigmatic leader of Team Delta. As they pursue their ambitious goal, questions arise about Kasper's true intentions and the motives behind his assistance.
Neil/Tyra, a gifted scientist of the Ivara Region, is trying to create a powerful Pokemon called Mewtwo. Neil/Tyra did it. However, this is not enough for Neil/Tyra. Because they want to make Mewtwo stronger, they want to turn it into a Pokemon which can mega evolve without ordinary mega stones, but unluckily, they have no money to keep it up. When they think they have to give it up, a man called Kasper shows up. This man is a businessman; what's more, he is the leader of Team Delta, a mysterious organization in the Ivara Region. He said he could help Neil/Tyra finish their experiment. Neil/Tyra has no choice; they join Team Delta. However, they are still wondering why did Kasper help them? Should they trust this man?