Ken and Mary of the Pokemon Mystery Club (PMC) are once again looking for a Pokemon from outer space, checking the site of a meteor crash. A Lunatone emerges and zaps them, erasing the memories of the encounter.
Meanwhile, Ash and friends reach Volley Town, finding it strangely deserted. They walk into the Pokemon Center for assistance, but Nurse Joy is zoned out and unhelpful. Brock doesn't believe it's the real Nurse Joy.
Team Rocket sneaks into the Pokemon Center, but bump into Ash and friends. When Nurse Joy approaches, they all run and hide in a storage room. There, they run into the frightened Lunatone. It tries to use Psychic on them, but passes out instead.
Nurse Joy returns to normal and treats Lunatone. It needs moonlight to survive, so they decide to take it up to Nearby Camerupt Point where the full moon shines. They hide the Pokemon from the PMC in a cart and pull it up the hill, but are cut off by Team Rocket. Team Rocket gets into a fight with the Pokemon Mystery Club.
The PMC sends Team Rocket blasting off. Pikachu, Mudkip and Beautifly team up to drive off the PMC, but they won't be defeated. The full moon rises and Lunatone charges up, and sends the pair off with Hidden Power. The kids then bid farewell to Lunatone.
- The design of Mary's Pokédex is based on the Game Boy Advance SP. It uses the "Dexter" voice rather than the "Dextette" of Ash's Hoenn Pokédex.
- When Brock shows the others a book with pictures of other Nurse Joys, the one from The Joy of Pokémon is shown.
- The episode name is a play on the phrase, "crazy as a lunatic," or "crazy as a loon."
- When Chimecho appears during Team Rocket's motto, it seems to have two "spikes" on its "back" rather than one.
- During the battle between Team Rocket and the Lunatone the 'R' on Jessie's shirt is reversed.
- Either there are two Pokémon Centers, or the scenario of the Pokémon Center changes from one place to another during the episode. At first, when the group enters the Center, there's a building behind them. Later, they are hiding behind a bush, right where the building was.