Drew is shown to be battling against a dressed man. His Roselia is losing to a Dusclops. Dusclops uses Shadow Punch, hitting Roselia. Dusclops uses Will-O'-Wisp, defeating Roselia and Drew. The man disappears. Meanwhile, the gang has appeared in Verdanturf Town. Max sees Drew giving Poké Balls to Nurse Joy. They are sure that Drew is entering the Contest, but they are surprised when Drew wouldn't, due to Roselia's wounds. He warns them of a masked Coordinator who calls himself as the Phantom.
May goes to practice. Team Rocket begins to practice as well, but they see the gang. Skitty is brought out and May order Skitty to use Blizzard, but Skitty does it on them. May will then throw balls to Skitty, so she needs to use DoubleSlap to juggle the balls with her tail. Skitty succeeds, balancing the balls. May throws some additional balls, but suddenly Skitty fails. Team Rocket sees them - Jessie is confident she and Dustox will win. A man from far sees them as well. Skitty tries once more to juggle the balls, succeeding in juggling 5 balls.
Skitty gets excited, but fails to juggle the balls. The man who battled Drew, the Phantom, appears to challenge the gang to a battle. Ash goes in to battle with Pikachu, so the rules are like the Contest's - 5 time limit. The Phantom brings Dusclops. Pikachu uses Quick Attack, but no damage is dealt due to Dusclops being a Ghost-type Pokémon. Dusclops uses Shadow Punch, with Pikachu being hit by the attacks. The Phantom orders Dusclops to end the fight, but a car is heard, so the Phantom calls Dusclops back and disappears.
A woman goes out of the car and chases the Phantom. The Phantom is cut and stops, so the woman goes after him, but she stumbles and the Phantom vanishes. The woman finds an object and is angry, asking loudly what have they done to her son, Timmy. Brock tells her that they have seen the Phantom only once and they have no idea who Timmy is. The woman begins to tell that Timmy, her only son, stopped going to school, so she hired an detective to look after Timmy. The detective noticed that whenever Timmy goes away, the Phantom appears.
The woman is told that they are Pokémon trainers, so she wants them to find the Phantom and discover who he is. Team Rocket sees the shiny rings and hear what the woman says, so they are after unmasking the Phantom. The gang arrived to the woman's house - a huge mansion. The man - Timmy - takes notes about Pikachu, but notices his pen is missing. The woman appears (with the gang introducing themselves to Timmy) and shows him the Pen he lost. The woman commands Timmy, as she found it where she chased the Phantom. The woman notices the bandage, but Timmy goes to his room.
The woman suspects (due to the wound on his arm) that Timmy is the Phantom. They convince the woman that they can't be, but she becomes upset when Ash asks her if Timmy wanted to become a Trainer. The woman is angry when Brock tells her that she can learn much from Pokémon. They discuss that Timmy is not a happy person. Out of nowhere, Timmy's father, Tommy, appears and knows who the Phantom is. The Phantom was Timmy all along. When Tommy was a Coordinator, he met his wife and he married her, but he couldn't allow Pokémon to enter the mansion - she hated them. He made the Phantom costume to get in the Contests. However, he hid it and Timmy found the costume, so he took in his footsteps.
Timmy encountered a Duskull and brought it home, but his mother did not allow, thinking he should study more. Timmy felt sad, so Tommy brought him the Phantom costume. Timmy became a Coordinator and gained more confidence. Timmy will sure to go into the Contest that will be in town. Brock has an idea to help him. Timmy's mother is being driven in the car and sees a woman giving her daughter a Poochyena. Timmy's mother thinks about it. May practices with Skitty - she uses DoubleSlap to juggle the balls.
The Phantom (dressed as Brock) appears and challenges May to battle. Timmy's mother goes out of the car, with Ash, Timmy and Tommy going out of the mansion. Timmy's mom is convinced that Timmy is not the Phantom. However, Brock's mask is taken off, but he puts it back - Team Rocket wants to expose the Phantom for the rewards. Jessie sends Seviper and James Cacnea to discover the Phantom's identity. Pikachu is about to use Thunderbolt, but Ash realizes it will hit Brock (the Phantom).
Skitty uses Blizzard, taking Seviper and Cacnea off, but at same time Brock is revealed, so he pulls his mask again. Pikachu uses Thunderbolt, blasting Team Rocket off. Brock leaves, so Tommy knows that his wife saw Brock's face. Surprisingly to Tommy, she leaves to her office, saying that is sure wasn't Timmy. Timmy surely knows that he'll enter the Contest, while May knows she'll enter, too.
- Featured Pokémon: Crawdaunt, Chinchou, Houndour, Volbeat
- The title could be a reference to the 2002 comedy film "The Master Of Disguise".